What to Watch Out for in Your Players

[Rerem115]

Problem players. Everybody knows about them. We've all seen them. Heck, maybe we've even BEEN them. In the relatively short time that I've been both a player and a DM, these are some of the red flags I've seen in problem players.

• Thinks that "lol, i so random" is both funny and sufficient characterization
• Steals from party members in game
• Steals from party members irl
• Tries to solve a problem by seducing it
• Plays a character that does not match their gender
• Has ever forced the DM to roll for pregnancy
• Drow
• Gives you a handwritten 15 page backstory, or links you to their Tumblr and tells you it's in there somewhere
• Uses the word "sexy" to describe their character on a regular basis
• Insists on using a class they found on dandwiki
• Wants to be actual royalty in their backstory
• Insists on using anything they found on dandwiki
• Asks to play a class focused on crafting
• Focuses on self-preservation over actually doing anything; e.g. running and hiding from every encounter, social or otherwise
• Dual Wielding
• Katanas
• Dual Wielding Katanas

What about you guys? What are your major signs that something isn't right in you party?

[kraitmarais]

A player who names their character after a character from a different franchise, e.g. Gandalf, Rand, Mileena, etc. Red flag for a problem player.

[JoshuaZ]

Problem players. Everybody knows about them. We've all seen them. Heck, maybe we've even BEEN them. In the relatively short time that I've been both a player and a DM, these are some of the red flags I've seen in problem players.

• Tries to solve a problem by seducing it
• Plays a character that does not match their gender
• Gives you a handwritten 15 page backstory, or links you to their Tumblr and tells you it's in there somewhere
• Wants to be actual royalty in their backstory

Curiously, all of the ones I've included in this quote were done by some extent with one of my players. The player was male. They made a female character with a long (but very nicely typed and entertaining backstory) which made them the lost heir of the ancient dynasty in the major empire. They were a female because they had a metagame goal of eventually marrying the Emperor of the current dynasty (who in the setting was not married and needed an heir). Their character was wonderfully built, using many things from the setting and helped flush many things out with their backstory. The player did a really excellent job of keeping the whole party together and generally on-track. So, yeah, things can be warning signs, but one should keep in mind they really are just warning signs.

[Saintheart]

• Drow

In game, or in real life?

[Rerem115]

• Drow

In game, or in real life?

Yes.


In all seriousness, though, all the people I've seen play drow either wanted to be sadistic puppy eating (in one case, literally) dillweeds, or else they were oh so tortured loners who were misunderstood by literally everyone, and just wanted to mope and be tragic whenever anybody noticed them.

[Lord Raziere]

some of these "warning signs" don't seem like warning signs at all to me, just character traits that people associate with bad players but are just traits that can be used good or bad. so I'm leery of this list.

[Rerem115]

I never said that this was by any means perfect or a definitive guide, these are just the traits that the problem players I've experienced possessed. Most of these traits are reasonably innocuous on their own but they provide fault lines that when exaggerated or done poorly, were real breaking points within the gaming group.

For example, the problem wasn't that one of the characters seduced a nobleman in town, it was that the player absolutely needed to know if she was pregnant. Like, pitched a minor fit, and made the DM roll. And then, it happened when the party got to the next town. And the next. Again, it wasn't that there was seduction present; it was the undue focus that was placed upon it that was the real issue.

[JoshuaZ]

I never said that this was by any means perfect or a definitive guide, these are just the traits that the problem players I've experienced possessed. Most of these traits are reasonably innocuous on their own but they provide fault lines that when exaggerated or done poorly, were real breaking points within the gaming group.

For example, the problem wasn't that one of the characters seduced a nobleman in town, it was that the player absolutely needed to know if she was pregnant. Like, pitched a minor fit, and made the DM roll. And then, it happened when the party got to the next town. And the next. Again, it wasn't that there was seduction present; it was the undue focus that was placed upon it that was the real issue.

Complete agreement. I wanted to make essentially that sort of point essentially explicit.

[Algeh]

• Tries to solve a problem by seducing it
  

In character or out of character? (Both are problems, but they are different problems.)

• Plays a character that does not match their gender

I do this on purpose with new/pickup groups, actually. It clarifies a lot for me when one of their characters starts hitting on my character and I can reply with something like "BeardAxe scratches his beard thoughtfully, dislodging some of the remains of dinner that he was saving in case he got peckish later, and says 'well laddie, I'm not sure if I'm getting your drift or not, but it may be I should warn ye that I drift a different way'" or something of the kind to help figure out if what they're actually trying to do is pick me up out-of-game starting with in-game pick-up lines (which is on my own personal "problem player" list, generally). Playing a male character is the equivalent to putting up a big "I'm not looking for an awkwardly-handled in-game romance plot" sign in my experience, and I definitely prefer to leave games with romance plots to groups of people I've already filtered for problematic behavior rather than new/pick-up groups. (If they're still interested in a romance plot after being reminded of the player/character gender mis-match and try an approach vaguely appropriate to trying to pick up the character rather than me, that's not an automatic problem. I just don't go for RL subtext presented in-game like that, since it almost always leads to problems both in-game and out-of-game.)

[Cluedrew]

I agree with the general idea of warning signs vs. an actual problem. I remember one campaign I played what appeared to be a gender-swapped version of a character who had destroyed the last campaign. It went wonderfully.

Ones I would add:

• Describes their character over and over again without adding details.
• Can only describe their character mechanically.
• Has trouble understanding why NPCs might not immediately do what their characters suggests.
• Takes weaknesses and them makes sure they never come up.
• Never considers what the other party might contribute to a situation or has to be reminded.

A couple of these rate pretty highly on my things to look out for. I guess my list different than the standard ones. I guess I haven't met too many who are bad in standard ways for whatever reason.

[kraitmarais]

Has trouble understanding why NPCs might not immediately do what their characters suggests.

I’ve definitely gamed with players who seemed perplexed about why a really good Cha check didn’t produce approximately the same result as domination magic.

[Faily]

Oh, you sweet summer child. I can tell it's only been a few years for you, but you know nothing of the true horrors of problem players.

... Mostly because a lot of the stuff on the list isn't actually really a problem for most games or gamers.

• Thinks that "lol, i so random" is both funny and sufficient characterization (This tends to be a lot of beginner-gamers in my experience, especially when they're younger. They'll grow out of it)
• Steals from party members in game (Same as above. Usually can be solved by talking to them and explaining that it's not cool)
• Steals from party members irl (OK, this one is less a problem player and more of a "we have an actual ****ing horrible person here". Leave my house now or I call the cops.)
• Tries to solve a problem by seducing it (I wouldn't call this a problem because our playgroups have had so many hilarious stories and situations coming from seductive-type characters. It's a different playstyle, that works better if everyone is more onboard with more mature themes)
• Plays a character that does not match their gender (... Well, I better tell most players I know that they are problem players by wanting to crossplay? I think most people I game with have done it at some point)
• Has ever forced the DM to roll for pregnancy (I... what? As in asking the GM if they have now impregnated something, or if they are pregnant? In general, I've been in groups where the GMs have rolled randomly for stuff like that, after all the players have given permission to be on board and comfortable with that sort of thing, but... I'm not quite sure what this one means?)
• Drow (Really?)
• Gives you a handwritten 15 page backstory, or links you to their Tumblr and tells you it's in there somewhere (the laziness of the latter is more of an issue than the former. With the former, I'd ask for the player to at least summarize it into bullet-points for me to start with)
• Uses the word "sexy" to describe their character on a regular basis (What about other adjectives?)
• Insists on using a class they found on dandwiki (This one I will agree with being a problem, because rarely does anything good come out of "I found it on the internet!")
• Wants to be actual royalty in their backstory (I have, and have had players who have, been guilty of this... and still are. As long as it fits the group and the setting, I'm all good)
• Insists on using anything they found on dandwiki (same as previous comment about "I found it on the internet!")
• Asks to play a class focused on crafting (Not a bad thing. Some players enjoy the tinkerer-type and like to provide support to the group that way. Crafting is not a bad thing)
• Focuses on self-preservation over actually doing anything; e.g. running and hiding from every encounter, social or otherwise (That is a problem, and should be adressed in why they do not want to partake in the adventure)
• Dual Wielding (Dual-wielding is not an issue. Seriously. Sheesh...)
• Katanas (Depends on the setting. If you're playing L5R, it's a must for any samurai. Or is this more of a trench-coat and katanas comment?)
• Dual Wielding Katanas (Trench-coats and katanas again...?)

[Quertus]

I never said that this was by any means perfect or a definitive guide, these are just the traits that the problem players I've experienced possessed. Most of these traits are reasonably innocuous on their own but they provide fault lines that when exaggerated or done poorly, were real breaking points within the gaming group.

For example, the problem wasn't that one of the characters seduced a nobleman in town, it was that the player absolutely needed to know if she was pregnant. Like, pitched a minor fit, and made the DM roll. And then, it happened when the party got to the next town. And the next. Again, it wasn't that there was seduction present; it was the undue focus that was placed upon it that was the real issue.

So, the situation could have been avoided if the GM had just, you know, checked for the possibility of pregnancy when it was first brought up. The problem was that the GM wasn't listening to the players.

Whenever there's a problem in a game, always check the GM's chair first - that's my motto.

What about you guys? What are your major signs that something isn't right in you party?

Well, most of your list doesn't even register on my "red flag" radar. Due to a bout of senility, I can't seem to remember what my main red flag - that I've even asked meta-level for help with on these forums - is.

I will say that players who cannot comprehend that there are multiple ways to play the game, and multiple sources of fun, tend to be problematic. And those who refuse to acknowledge that their play style is detrimental to the fun of others - or acknowledge it, but don't care - are beyond just a red flag.

dating stuff

I was going to reference a story another Playgrounder told, where playing a cross-gender character was literal lifesaver. I guess I'll add this story to my list of stolen acquired stories to tell regarding the benefits of cross-gender characters.

[Kaptin Keen]

I’ve definitely gamed with players who seemed perplexed about why a really good Cha check didn’t produce approximately the same result as domination magic.

I know a girl who - on several separate occasions - has walked into a fashion fair, smiled prettily at a designer, and walked away with 1-2 original designer dresses over her arm, worth thousands of dollars, and paid not a dime. I doubt she's ever decided she wanted something, and not gotten it.

Beauty, above a certain mundane level, does things that you'd need magic to reproduce in real life.

Not saying you should allow it in-game for that reason. I just feel it's an interesting anecdote.

[Cluedrew]

... Mostly because a lot of the stuff on the list isn't actually really a problem for most games or gamers.

Remember: Warning flags. None of these things are going to be a problem (except the real life ones) but they can be hard to do right and some of the harmless ones more often come with problems. Still, if only problem is they only play cross-gender with twin weapons I would not be worried.

I’ve definitely gamed with players who seemed perplexed about why a really good Cha check didn’t produce approximately the same result as domination magic.

I know a girl who - on several separate occasions - has walked into a fashion fair, smiled prettily at a designer, and walked away with 1-2 original designer dresses over her arm, worth thousands of dollars, and paid not a dime. I doubt she's ever decided she wanted something, and not gotten it.

The second post made me realize the magnitude of the issue I was referencing was a bit off. The character wasn't a socialite, they might have even dumped the social stats. Not that it mattered because they didn't try to use them.

PP: I go up to a the guy with some weapons and challenge him to a fight.
GM: He doesn't accept and continues walking...
PP: {Confused}

It was weird. I think the other case where social skills might just be a mismatch in how "powerful" a given stat is. Sort of like expecting to smash a bolder with your bare hands with high physical stats (it might be possible, depends on the system).

[Telok]

1. Wants to play an evil murder-elf/half-demon/soul-sucking night horror in a setting were drow, tieflings, and undead are hunted down and killed on sight by all civilized races. (Did not read the first two sentences of the one page setting)

2. Has a completely filled out character sheet but cannot describe any aspect of the character's appearance, personality or goals. (Wants to play an in-person computer fighting game)

3. Does not have a filled out character sheet and cannot tell you what the abilities on the sheet do. (Does not read rules)

4. Wants to play an exact of a character from a book or movie and 'found a build online'. (Likes the idea of rpgs but probably hasn't thought about they're actually going to do)

5. A combination of two or three of the above after they have been playing for six or more months.

[Jay R]

• Dual Wielding Katanas

Yup, this is a problem. A samurai's two swords should be a katana and a wakizashi.

[BlizzardSucks80]

1. Is an overly-vindictive player and plays an edgelord character who will give an extreme beatdown/humiliation to any NPC or other player character for even the smallest slights.

2. Doesn't listen and straight up ignores other players and generally belittles others and treats them like they are meaningless fools.

3. Is not open to new ideas and wants to stick to the same cookie-cutter formula of play and/or setting style.

4. Makes completely off-the-wall characters that the GM will have to sweat and work very hard to squeeze that character into the setting. Extra points if it is pro-bono or on the spot.
Extra points if the character is really hard to get along with or is a straight up monster freak that won't fit in very well in society.

5. Making a character that is a monstrous villain type that really has no business being a player character, and really should be an NPC villain.

6. Rolling the dice in a spot where the GM cannot see the actual die roll, and declaring the result without the GM actually knowing the result for certain. This usually results in lying about the actual result to gain advantage. Extra points if the dice roll takes place in a spot where the GM has to constantly lean over to see the actual die roll result, and after a while the GM really can't be bothered anymore and just accepts whatever the rolling player has said. Extra points if the dice keep rolling off onto the floor.

These are all things that annoy and frustrate the crap out of me both as a GM and a player. I know people aren't perfect, but over the years I have gotten quite cynical and jaded about tabletop games and as a result I'm just not as into them as I used to be. But for some reason I keep playing them anyway.

[kyoryu]

The number one thing to watch for is an inability to compromise.

If there are class/race/whatever restrictions in you game, and the player unduly fights against them? Danger. Same if you decide to veto something on their character sheet, or in their background (make sure you're willing to compromise, too!)

Otherwise, I start watching for that inability to compromise as quickly as possible. And the smaller the thing, the better! If they can't compromise on buying shoes, they won't compromise when their character's life is on the line.

Most problems with players seem to stem from this. At its core it's a basic lack of empathy and will only create more and more issues down the road.

[Quertus]

It still blows my mind that people want to cheat in TRPGs. Otoh it's widely accepted when GMs roll out of sight behind a screen and sometimes use that to be able to cheat, so it's hardly surprising that some players would think its okay.

I'm not a fan, but I think I understand the mindset. GMs cheat because they think that they know better than Arangee what would make a good story. By that logic, why shouldn't the players have the narrative power to overrule Arangee?

Personally, I want to come by my victories (and losses!) honest. I can't stand the GM cheating, the idea of 99.99% of the world running on narrativium just isn't worth interacting with. But another PC? Some small statistical anomaly like that may as well be a class feature. Myself, I'd be fine with all the players rolling behind a screen, and the GM rolling in the open.

[VincentTakeda]

Problem players. Everybody knows about them. We've all seen them. Heck, maybe we've even BEEN them. In the relatively short time that I've been both a player and a DM, these are some of the red flags I've seen in problem players.

• Thinks that "lol, i so random" is both funny and sufficient characterization
• Steals from party members in game
• Steals from party members irl
• Tries to solve a problem by seducing it
• Plays a character that does not match their gender
• Has ever forced the DM to roll for pregnancy
• Drow
• Gives you a handwritten 15 page backstory, or links you to their Tumblr and tells you it's in there somewhere
• Uses the word "sexy" to describe their character on a regular basis
• Insists on using a class they found on dandwiki
• Wants to be actual royalty in their backstory
• Insists on using anything they found on dandwiki
• Asks to play a class focused on crafting
• Focuses on self-preservation over actually doing anything; e.g. running and hiding from every encounter, social or otherwise
• Dual Wielding
• Katanas
• Dual Wielding Katanas

What about you guys? What are your major signs that something isn't right in you party?

Lets see....

• Tries to solve a problem by seducing it GUILTY but never when playing a female character
• Plays a character that does not match their gender GUILTY
• Wants to be actual royalty in their backstory: sort of GUILTY. Played warhammer once and Noble was a starting class option. Oddly enough one of the few times I also played non matching gender. Most hillarious nobility related situation was when she referred to the dwarf in the party as "my dwarf"... He did a double take and indignantly remarked 'MY dwarf?'... I'm like well. She's a noble. Posessive perspective is sort of their natural state of mind.
• Asks to play a class focused on crafting GUILTY but only in pathfinder.
• Focuses on self-preservation over actually doing anything; e.g. running and hiding from every encounter, social or otherwise GUILTY
• Katanas GUILTY but i'm leaning more towards bokkens and shakujo these days

[Aneurin]

My big red flags? Probably these, in no particular order. And a few others that haven't come to mind, I'm sure.

These aren't things that'd flat out stop me playing with someone, of course, but they are things that would make me think carefully before agreeing to game with someone.

• Someone using 'Good' or 'Evil' to describe their character's personality. Those words tell me absolutely nothing about how I can expect a character to act, and make me think that very little thought has been given to making a unique individual PC.
  
• Large amounts of gore, sex and otherwise taboo subjects in a backstory. I once had a character submission whose background featured murder, incest and cannibalism (not that their character participated, but still...). Suffice to say they were not included in the game in question. That's a pretty extreme example, though.
  
• Characters described as 'beautiful' or 'handsome'. Not everyone has the same standards of beauty as you do, and I find a little more often than I'm happy with that a 'beautiful' character has a player who expects NPCs and/or other PCs to fawn over them.
  
• Players who gets squicked out by cross-play... or at least the idea of it. Some of the actual practice is extremely dodgy, I'll admit (then try and suppress the memories I just conjured up). But someone who vocally opposes cross-play tends to throw up some red flags - don't get me wrong, I don't expect everyone to cross-play or even be completely comfortable with it, but someone shouting about how men can't play women makes me think there might be other issues that may make them an undesirable member of a gaming group (if only because I don't want the drama of them working through said issues interfering with my gaming).
  
• Poor hygiene in a player. Honestly, I just don't want to spend lots of time around someone smelly or gross.
  
• Poor communication skills. Tabletop RPGs are (almost all) social games; you need to communicate. If you can't or won't... well, why are you here? I'm not opposed to helping people improve their skills, heck I'm more than happy to, but I need to be sure that the person's actually going to work on their skills rather than just blame problems on their lack.
  
• Blatant rip-offs of someone else's intellectual property. I don't want to have Obi Wan Kenobi in my game; I know how his story goes. Let's tell a different, new story! Obviously, this one is significantly less relevant in the event of a game playing established fictional characters.
  
• References. Great, you like [Insert Media Here] a lot - I get it, really. Now make your own damn dialogue! I don't mind a few references here and there, but I expect to see something original and creative from people - is that too much to ask?
  
• Being sexist, racist, culturally insensitive, bigoted or whatever else. Also, trying to play a character who is these things. Or loudly protesting that they aren't, in fact, these things (especially unprompted). Probably don't need to mention these are red flags, but they very definitely are. Pretty big ones.
  
• Won't compromise. Doesn't really matter what over, if someone isn't willing to try and come to an agreement... Well, this could cause trouble down the road. Annoyingly hard to spot this one early, though, unfortunately.
  
• Doesn't pay attention. If you won't pay attention to the setting pitch or even what system is in use (honestly, the number of times people assume I'm using/talking about D&D when I'm not is bloody ridiculous), why should I think you'll pay attention to the game or to the other players?

[Keltest]

A player cheating bothers me, whether GMing or playing. But nowhere near as much as a GM cheating. I won't return to a game where the DM is pretty clearly "fudging" their rolls.

The funniest part is there are GMs that claim the players won't even notice.

In general, I subscribe to the GM philosophy of "if you don't want a variable result, don't roll for it", but at the same time I don't like my players being able to guess the direction things will be heading just because I rolled some dice (ie theyre searching for hidden enemies, rolling hide checks only when there are enemies to be found reveals very clearly when there are and are not enemies.) So just because there is an action and a roll, I wouldn't necessarily force the GM to make them related.

[Hawkstar]

My big red flags? Probably these, in no particular order. And a few others that haven't come to mind, I'm sure.

These aren't things that'd flat out stop me playing with someone, of course, but they are things that would make me think carefully before agreeing to game with someone.

-snip-

• Characters described as 'beautiful' or 'handsome'. Not everyone has the same standards of beauty as you do, and I find a little more often than I'm happy with that a 'beautiful' character has a player who expects NPCs and/or other PCs to fawn over them.

Isn't that part of the fun of high-Charisma characters? Just as high STR characters can do things like throw people around and break them in dozens of different ways, or high INT characters can outwit other people and control the fabric of reality?

[/list][*]Blatant rip-offs of someone else's intellectual property. I don't want to have Obi Wan Kenobi in my game; I know how his story goes. Let's tell a different, new story! Obviously, this one is significantly less relevant in the event of a game playing established fictional characters.[/list]

Unfortunately, we don't know Obi Wan's story because his movie got canned because The Last Jedi alienated fans and Solo bombed. But aside from that - you may know how Obi Wan trained Anakin to become Darth Vader, but do you know the story of how Obi Wan stormed Malekith's castle of doom alongside Robin Hood, The Fresh Prince of Persia, and Ron Weasley?

• References. Great, you like [Insert Media Here] a lot - I get it, really. Now make your own damn dialogue! I don't mind a few references here and there, but I expect to see something original and creative from people - is that too much to ask?

Is it really D&D if the players AREN'T constantly quoting Monty Python or The Princess Bride?

[/list][*]Being sexist, racist, culturally insensitive, bigoted or whatever else. Also, trying to play a character who is these things. Or loudly protesting that they aren't, in fact, these things (especially unprompted). Probably don't need to mention these are red flags, but they very definitely are. Pretty big ones.[/list]

So, I can't play Frodo Bigguns (First name pronounced like a-FRO hair-DO), the halfsploitation hero straight out of Neverwinter who's teaming up with all his other mijits (But don't call him that. You ain't got m-word privilege) to constantly fight against The Big Man keeping the Little Guys down?

[Mr Beer]

Plays a kender.

[VincentTakeda]

Plays a kender.

Where's my darn 'like' button when I need it

[Nifft]

It still blows my mind that people want to cheat in TRPGs.

Some people play RPGs specifically to enjoy a power fantasy.

Failing isn't part of their fantasy, so they want to avoid it -- alternately, lying to the group and having the group accept it is a power-move that ticks their need for feeling like they're in control of something.

These are sometimes people who don't like much about their own real life.

I'm torn between pity and revulsion.

[Mr Beer]

Where's my darn 'like' button when I need it

;)

It's the classic jerkface player choice.

It's not my fault, it's what my character would do! [does more jerkfacing]

Some people play RPGs specifically to enjoy a power fantasy.

Failing isn't part of their fantasy, so they want to avoid it -- alternately, lying to the group and having the group accept it is a power-move that ticks their need for feeling like they're in control of something.

These are sometimes people who don't like much about their own real life.

I'm torn between pity and revulsion.

The one guy I ever kicked was a known RPG cheat. I didn't boot him for cheating, it was some of his other symptoms of being an unhappy person.

[Wraith]

• Tries to solve a problem by seducing it

I feel that this one is a matter of context, rather than specifically being an outright problem. On the one hand, it's usually just a sub-set of the "lol random" problem:
"The party enters the cave, and are immediately surrounded by darkness..." "I roll to seduce the darkness!". It's a silly joke made in many, many different ways, but it's pretty harmless unless the acting out of the scenario begins to encroach on the plot and demanding more time from the party. In that case it's not the seduction which is a problem, but rather it's a symptom of a player demanding too much of the spotlight. When this happens, it's usually very obviously different to just the joke itself.

And on the other hand, playing a character whose means of progression is through seduction - classically Bards in D&D but also including things like Toreador in Vampire - is not inherently bad. It's just something to discuss beforehand, to make sure that it doesn't stray into material that makes the players or GM uncomfortable.

The seduction itself isn't the problem - why they're doing it, and how they're going about it, is more important.

• Plays a character that does not match their gender

Again, I don't think this is the issue, so much as the motivation for doing it. If they're player a gender-flipped character because it's an RP opportunity or because they've found a particularly nice miniature that they want to represent themselves with, it's pretty harmless.
If, however, they're doing it because they can use it as a way to demand spotlight time or to disrupt other players' actions, then the problem isn't with the player's choice of gender but rather their overall attitude.

• Wants to be actual royalty in their backstory

I doubt that it's specifically 'royalty' that is the problem, rather the fact that they want to be perceived as a person of authority in order to boss around other players or to try and circumvent NPC interactions. It's perfectly possible to play a member of royalty - most game systems let you take "Rank" as a perk or stat, after all, encouraging it mechanically - and not be an overbearing jerk, so long as the player is capable of not being a jerk...

• Asks to play a class focused on crafting

This one surprises me. In my experience, "crafting players" are the ones who sit quietly and pore through books during downtime rather than cause problems at the table; the biggest problem I've ever had is that they're occasionally too engrossed in a book to notice when it's their turn to act, which can usually be solved by a well-aimed dice to the nose.
If it's become a red flag about the player to you, I once again imagine that it's the player specifically, and that the class just happens to be their current method of disruption; the correlation between the two is otherwise lost on me, I'm glad to say.

• Focuses on self-preservation over actually doing anything; e.g. running and hiding from every encounter, social or otherwise

Again, I feel that context is more appropriate here. Playing a selfishly evil or possibly just cowardly character can be a lot of fun, providing that they're contributing to the game in other ways; I quite like playing the latter, as it usually gives me an excuse to go somewhere or do something to drive the plot, because where I want to be isn't where the rest of my murder-hobo party is currently hacking through the local constabulary.

Dong it because the encounter looks difficult, or because they want to "win" the game without being challenged, on the other hand? I've seen that before, and that's usually the same person who keeps trying to be the King of the country; they want the authority to make things go their way, which suggests that they're not very good at sharing or working as a team.

That all being said, there are a couple of things that I have seen that still strike me as Red Flags:

• Wanting to play an "insane" character

Mental health can be a precarious subject, and role-playing games have very rarely handled it in a sensitive and properly inclusive manner; even less so in the hands of a player who is looking for an in-built excuse to be "Hollywood Insane", that sort of quirkiness that they think let's them get away with their wacky escapades by saying "well of course I hit the God-Emperor in the face with a live chicken - I'm insane!".

Playing a genuinely mentally unbalanced character can be done appropriately. Sometimes it's even encouraged, in games such as Dark Heresy and Call of Cthulhu where admitting that your experiences are unhealthy can actually lead you to better coping with them. Doing it in D&D is, I usually find, another sub-set of the "lol random" archetype that manages to trample over stereotypes and demean other peoples' suffering while they go about it.
If that's all you're trying to do, and you think that you can try to justify it with paper-thin veil of poorly researched illness, my GMing eye will well and truly be upon you.

• Boasting about their character being able to kill mine in a fight

A little bit of competition and vying between roles isn't necessarily a bad thing, especially in an established group who are content to bicker and tease each other in an amiable way.
If your character's defining trait, or sole means of interaction, is "I can kill you, so do what I say or else" then that's a different situation. It's one thing to be a boastful character, but another entirely to try to intimidate other players into doing your bidding by using the safety and free agency of their characters as a bargaining tool.
If you do that, I am going to perceive that as you choosing to forgo the major objectives of the game, such as socialising with other people and following the story laid out by the GM, in order to massage your own ego. Power trips over other characters - preventing them from playing the game their way by bullying them into doing it yours or else you'll remove them from the game - suggest to me that you're not there to play the game, just to belittle other players, and I've never played in a game where I haven't made it perfectly clear how unwelcome that behaviour is.

• The "My Character Wouldn't Do That" Guy

Another sort of player who expects the game to revolve around them, and them alone.
Role-Playing should run by the social contract; the Players should take part in the game that's being run by the GM, and the GM should run a game that the Player want to take part in.

It's crucial to remember both parts of that theory to prevent the GM from being taken for granted, and to stop the GM railroading the players through his own little fantasy novel.
If the GM is making a reasonable effort to run an entertaining for the group, however, and your response to what is suggested is "No, my character doesn't want to do that", then my advice to you is to go away and roll up a character that does. The game cannot come to a complete halt because your fictional character has come up with an equally fictional and usually entirely arbitrary reason to refuse to take part.

There's always caveats available, of course. "I don't want to do it in that way" is a perfectly valid response, because that means you can suggest an alternative and still take part in the game, albeit from a new angle. Just pointing out the 'problem' and not offering a solution, however, is called 'whining' and to do that at the expense of someone else' freely given time is ungrateful and rude.

[EldritchWeaver]

But aside from that - you may know how Obi Wan trained Anakin to become Darth Vader, but do you know the story of how Obi Wan stormed Malekith's castle of doom alongside Robin Hood, The Fresh Prince of Persia, and Ron Weasley?

Ron Weasley? Who would play Ron over Harry Potter in such a group?