Biggest tabletop system pet peeves

[Xuc Xac]

You are completely right and I have yet to see a system that uses 2 resolution mechanics for skills and combat.

Most versions of D&D. I think 2nd edition actually had 3: THAC0 for combat, percentile dice for thief skills, and roll-under ability checks for proficiencies. Some versions use a d6 roll for skills. Do you consider ambushing and/or detecting an ambush to be a skill? That's a fourth mechanic for surprise/being surprised, but they didn't consider what would happen if a good ambusher tried to ambush a good ambush spotter (they only cover good skill on one side and default skill on the other).

So...do you dislike character advancement on a mechanical level?..

Advancement doesn't have to involve getting better options (e.g. "+1 melee" becomes "+2 melee"). It can be gaining more options (e.g. your fighter with "melee" learns "camouflage" or "tracking" to become more rangery).

[Khedrac]

Thinking about it, there's another fun one from AD&D - and that's a part of the system where the different factors that influence it are not compatible with each other...

I bring you "Suprise":
I htink most characters were suprirsed only on a 1 on a D6
Some characters were suprirse don a 1 on a D8 or a D10
Some monsters suprprised on a 1 or 2 on a D6 (or a 1, 2 or 3)
So - how do the monsters with a greater surprise chance interact with chacters with reduced surprise?

Don't get me wrong, I liked most of AD&D 1 & 2, but there were some rules that just did not work.

[Socratov]

Most versions of D&D. I think 2nd edition actually had 3: THAC0 for combat, percentile dice for thief skills, and roll-under ability checks for proficiencies. Some versions use a d6 roll for skills. Do you consider ambushing and/or detecting an ambush to be a skill? That's a fourth mechanic for surprise/being surprised, but they didn't consider what would happen if a good ambusher tried to ambush a good ambush spotter (they only cover good skill on one side and default skill on the other).

(snip)

I have never played 2nd edition (I only met with DnD and TTRPG's in general a when 3.5 was already done and 4th was just launched), so I can't really comment on wether or not it plays well. I have noticed that when a game uses the same system for combat and skills that one is going to suffer. In DnD that is a bad thing as both are supposed to be important. In CoC combat is not much more then an after thought, especially when the more supernatural enemies show up it quickly becomes a situation where the attacks are made up and the numbers don't matter. However, in DnD, and similar games, the expectation exists that you are not out of your depth and you have a real option of surviving and even winning the encounter. At least, that is what the epic fantasy genre implicates. And finding a unified system that is statistically sound, equally for situations where you are expected to fail without many consequences, i.e. combat where a missed attack isn't the end of the world, and for situations you are expected to succeed at under dire consequences where failure and success are synonyms for death and life, like saves and in some situations skills. Especially with compound skillchecks or a situation where it seems the best thing to do is to resolve a series of skill challenges. Where the degree of success means an easier time the next time. IMO the bell curve is fantastic for skillchecks: I'd much rather have a reliable skillcheck which I could depend on in tough times, then a high probability ceiling. In terms of probability distributions I'd rather have a linear progression for attacks, and a bell curve for skills.

[Cluedrew]

Tabletop: I don't like the battlemat thing. I occasionally comment that D&D seems to be two games welded together (that might be better on their own) and I think that battlemat is a great simple of that, only applies in one of the two sides. Drawing a map is OK (you are probably going to want one anyways) put mapping out positions on a grid doesn't really add anything in my mind. Except time spent.

Pre-Planned Plots: I can't think of any story that A) would be largely the same with different protagonists and B) was good. I think the best results where I didn't actually care, or really pretend to, about the plot but I did care about the setting. So I wondering from plot point to plot point was fun not for what happened, but the things already there. Not quite the same though.

To Khedrac: I can see how with just a bit of rewording you could make those two sides fit together flawlessly. I wonder if that was there intention.

[Kadzar]

You are completely right and I have yet to see a system that uses 2 resolution mechanics for skills and combat. From a statistics standpoint and usability I find that CoC 7th does a great job: d100 resolution where you skills and combat are graded by a threshold. the higher your threshold (i.e. the higher your score), the more often you will be successful. Sure the n00b can still beat the expert, but the chances for that are very, very slim (let's say expert is at 75%, n00b is at 5% for a normal skill check, that means 0.05*(1-0.75)=1,25% of that happening). If you are at advantage/disadvantage that is done though rolling an extra D100

Stars Without Number uses a d20 for attacks (and, I believe, saves) and 2d6 for skills.

[calam]

Tabletop: I don't like the battlemat thing. I occasionally comment that D&D seems to be two games welded together (that might be better on their own) and I think that battlemat is a great simple of that, only applies in one of the two sides. Drawing a map is OK (you are probably going to want one anyways) put mapping out positions on a grid doesn't really add anything in my mind. Except time spent.

Yeah, some games have battlemats without being that important and most editions of D&D seem to be it since its mostly for spell area of effect and the people who keep finding that play in campaigns with a significant amount of cliff-side battles. I wonder if there's a tabletop game that really takes advantage of it

[Steel Mirror]

Yeah, some games have battlemats without being that important and most editions of D&D seem to be it since its mostly for spell area of effect and the people who keep finding that play in campaigns with a significant amount of cliff-side battles. I wonder if there's a tabletop game that really takes advantage of it

4E really used the battlemat well. I've heard from a few people that played 4E without a mat and apparently it worked just fine for them, but for my group the grid was absolutely indispensable in basically every fight we ever had, and it wasn't unusual for the outcome of a fight to come down to proper placement of a 5 foot shift, or careful nudging of an opponent by 1 or 2 squares at the opportune moment. That campaign also was very strongly on the "TRPG as tabletop skirmishes with plot and character as thin (but enjoyable!) connective tissue between fights" side of the spectrum, so I don't think I'd say it was typical, but we absolutely wouldn't have had the same experience if we didn't take advantage of the mat.

[Guizonde]

4E really used the battlemat well. I've heard from a few people that played 4E without a mat and apparently it worked just fine for them, but for my group the grid was absolutely indispensable in basically every fight we ever had, and it wasn't unusual for the outcome of a fight to come down to proper placement of a 5 foot shift, or careful nudging of an opponent by 1 or 2 squares at the opportune moment. That campaign also was very strongly on the "TRPG as tabletop skirmishes with plot and character as thin (but enjoyable!) connective tissue between fights" side of the spectrum, so I don't think I'd say it was typical, but we absolutely wouldn't have had the same experience if we didn't take advantage of the mat.

seems like there really are two schools here. i come from the "if you can't describe it, show it" school. meaning, unless your dm is good enough to describe accurately a battleground and your team is tight-knit enough, you'll need a battlemap. i've rarely had needs for battlemaps. i'm pretty sure in over 10 years of weekly play, i've needed one 6 times. that said, we've come upon a real need with rogue trader, to the point we're chipping in and buying old battlefleet gothic figurines and gear just for the space fights. you simply can't describe accurately a voidfight, you can't keep track of all the parameters.

now, if anyone could help me out with a pickle i'm in... how do you guys represent 3 dimensional fights on battlemaps? my old team used to fight with a team split on 3 levels (under, over, and on ground). battlemaps were simply not doable, and we never could build scale models since it usually was corridor fights. here, it really was a case of "describe it because you can't show it". in my pf game, next level, half the team will be able to perform "death from above" style feats of dynamic entry and my dm is worried he'll only be able to narrate it. any words of counsel i can transmit? because out of the 7 in the group, we're all at a loss. i voted for description, but when it comes to bonuses, it'll be hectic to calculate without a visual aid.

[Jay R]

now, if anyone could help me out with a pickle i'm in... how do you guys represent 3 dimensional fights on battlemaps? my old team used to fight with a team split on 3 levels (under, over, and on ground).

The mini for a flying character is on top of a die, or some other prop that lifts it up. One of our players has several clear cubes that we use.

I've never dealt with an underground character. I'd probably get a flat marker to put under him - a poker chip or circle cut from construction paper.

Thinking about it, there's another fun one from AD&D - and that's a part of the system where the different factors that influence it are not compatible with each other...

I bring you "Suprise":
I htink most characters were suprirsed only on a 1 on a D6
Some characters were suprirse don a 1 on a D8 or a D10
Some monsters suprprised on a 1 or 2 on a D6 (or a 1, 2 or 3)
So - how do the monsters with a greater surprise chance interact with chacters with reduced surprise?

They get surprised more often. Why is this hard?

I think I'm failing to understand your difficulty. In what way is a character who is more alert incompatible with a different character who is less alert? Some people are more alert than others.

[Khedrac]

They get surprised more often. Why is this hard?

I think I'm failing to understand your difficulty. In what way is a character who is more alert incompatible with a different character who is less alert? Some people are more alert than others.

The fact that they incerease the surprise chance is not a problem, the working out what dice to roll is the problem. The various parts don't interact well - it would have been better with fewer rules.

[Jay R]

The fact that they incerease the surprise chance is not a problem, the working out what dice to roll is the problem. The various parts don't interact well - it would have been better with fewer rules.

Each one rolls a different die, just like if they all use d6s. Sometimes the least alert character is the one who notices the enemy first.

[Hunter Noventa]

I don't like games where disparate systems can leave chunks of the party with nothing to do for long periods of time. Shadowrun was pretty bad at this when I played. 'oh the mage is going astral/the decker is hacking, the rest of us can just sit and wait' was always a problem. And it boiled down to that because you have to guard the mage/decker's body while they go astral/hack, or even if you're doing remote hacking, time passes faster in the matrix, so you're still there as player, doing nothing, because only a matter of seconds or minutes passes for your character. it's terrible design.

[Xuc Xac]

Each one rolls a different die, just like if they all use d6s. Sometimes the least alert character is the one who notices the enemy first.

I think you missed the fact that it's not alertness. "Surprise" is active ambushing. "Surprised" is noticing the ambush.

Some characters get surprised less often than normal. Some can cause surprise more often than normal. The rules aren't set up as "X rolls its ambush skill vs Y's notice skill". The rules ask you to roll one die to see if the defenders are surprised or not. They add extra rules for modifying the roll if an "extra alert" character gets ambushed OR if an "extra sneaky" character did the ambushing. They fail to take into account what happens if an "alert" character is ambushed by a "sneaky" one.

[Random Sanity]

My pet peeve is fumble mechanics. It doesn't matter how small the chance is - if your own turn can potentially mess you/your party up worse than an enemy's turn through sheer RNG, the game developers screwed up. Period.

Nobody with a measurable chance of blowing himself up, skewering his own teammate, or just randomly dropping his shield for no reason would ever live long enough to begin a career as a PC.

PCs are supposed to be a cut above the random mooks wandering around the game world. Random displays of incompetence are for the loudmouthed idiot in the street who dies in his first significant encounter, not the main characters.

[Guizonde]

My pet peeve is fumble mechanics. It doesn't matter how small the chance is - if your own turn can potentially mess you/your party up worse than an enemy's turn through sheer RNG, the game developers screwed up. Period.

Nobody with a measurable chance of blowing himself up, skewering his own teammate, or just randomly dropping his shield for no reason would ever live long enough to begin a career as a PC.

PCs are supposed to be a cut above the random mooks wandering around the game world. Random displays of incompetence are for the loudmouthed idiot in the street who dies in his first significant encounter, not the main characters.

those are recurrent themes here. ffg's warhammer games (fantasy and dh) handle it pretty well. only on a 100 will you screw up completely, and based on the quality of your weapons, it'll either ignore one fumble, or you'll jam your gun. a good quality hellgun will jam on a 96+, a good quality automatic gun on a 94+, and really experimental or damaged guns can go as low as 85, iirc. in warhammer, jezzail rifles don't just jam, they fail catastrophically, as it should for a gun that's powered by warpstone. fate points help a lot with that, but let's imagine that you screw up in close quarters. you don't hurt yourself with your sword, you'll give an advantage to your opponent. this could mean you having to roll better to dodge or parry, getting disarmed... and of course the "oh no, this isn't good" moment, such as having a grenade going off in your pants because your opponent hooked the grenade's pin with a blow you couldn't handle. this would be two 100's in a row, or the pc rolling a 1 on a mook who's packing grenades. it fits with the setting, and even though i like fumble mechanics as much as i like critical hit mechanics, the typical dnd style "you suck 5% of the time" is simply not representative. my current dm usually gives a +2/-2 on further rolls after natural 1's in fights to represent that your character overstepped, fumbled a block, or another near-miss like that. it feels a lot more natural than a barbarian chopping off his foot because he fumbled a roll. statistically, nobody would ever to get to level 20 if they got into a fight a week. they'd strangle themselves with an anvil before that, judging by some stories of dm abuse i've read here.

[Gnoman]

The mini for a flying character is on top of a die, or some other prop that lifts it up. One of our players has several clear cubes that we use.

I've never dealt with an underground character. I'd probably get a flat marker to put under him - a poker chip or circle cut from construction paper.

Checkers or the right kind of poker chip (the sort that lock together) work well. Use one color for "up" and one for "down".

[Quertus]

I suppose, if I had to pick one pet peeve, it's that I don't like systems where I don't get to play the game that I signed up for.

What's this? A world that's supposed to be steeped in magic, yet everything feels so... mundane? (many GM's D&D games, Earthdawn?). Nah, I'll pass.

What's this? Oh, cool, a point buy for a generic system... that I can neither use to emulate any of my favorite characters, nor to build some cool ideas I have for which I haven't found am appropriate system? (GURPS, etc). Eh, I'm not feeling it.

What's this? The character creation minigame takes 3 sessions and a PhD, minimum? Why?

What's this? I'm sitting out, twiddling my thumbs, not playing any game, let alone the one I signed up for, most of the game? (Shadowrun). No, that doesn't sound fun.

What's this? The better I get at something, the more of a liability I am / the worse I seem? (D&D with fumbles added). Horrible times.

I want the character I create to match my vision of that character, to play the way I expect them to play, straight out of the box. And I want it to be possible (but not necessarily easy) to build the character that I want (so long as it fits the genre).

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Oh, another pet peeve: systems which give the GM toxic advice (D&D, I'm looking at you).

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And, of course, Alignment, bane of role-playing.

HP on monsters.

Explain? Do you mean that you want all opposition to have "narrative" health, and did when it's grammatically appropriate?

I am very surprised nobody has taken the opportunity to name the Wish Spell.

It never leads to a satisfying ending, it readily creates situations where the session just devolves in Contract law; the game and it either ****s up everything in its entirety, or it ends everything for always and forever.

Never? No, I can't say that I agree with that assessment. Why, one campaign ended with my character getting a Ring of Three Wishes, using one to fulfill its McGuffin purpose, and, by using the second Wish for the party, allowed the reveal that my character was illiterate. So, good times all around.

[Cluedrew]

They fail to take into account what happens if an "alert" character is ambushed by a "sneaky" one.

Maybe? If they had just phased it as rolling some alert die and rolling under a score. The former coming from the watcher and the latter the sneak. I can't help but feel that was the intended interaction because it just follows so naturally from the set up they have. But if those are actually the rules given (Khedrac's post)... it almost went out of its way to make that not happen.

[calam]

those are recurrent themes here. ffg's warhammer games (fantasy and dh) handle it pretty well. only on a 100 will you screw up completely, and based on the quality of your weapons, it'll either ignore one fumble, or you'll jam your gun. a good quality hellgun will jam on a 96+, a good quality automatic gun on a 94+, and really experimental or damaged guns can go as low as 85, iirc. in warhammer, jezzail rifles don't just jam, they fail catastrophically, as it should for a gun that's powered by warpstone. fate points help a lot with that, but let's imagine that you screw up in close quarters. you don't hurt yourself with your sword, you'll give an advantage to your opponent. this could mean you having to roll better to dodge or parry, getting disarmed... and of course the "oh no, this isn't good" moment, such as having a grenade going off in your pants because your opponent hooked the grenade's pin with a blow you couldn't handle. this would be two 100's in a row, or the pc rolling a 1 on a mook who's packing grenades. it fits with the setting, and even though i like fumble mechanics as much as i like critical hit mechanics, the typical dnd style "you suck 5% of the time" is simply not representative. my current dm usually gives a +2/-2 on further rolls after natural 1's in fights to represent that your character overstepped, fumbled a block, or another near-miss like that. it feels a lot more natural than a barbarian chopping off his foot because he fumbled a roll. statistically, nobody would ever to get to level 20 if they got into a fight a week. they'd strangle themselves with an anvil before that, judging by some stories of dm abuse i've read here.

I think you're remembering houserules a bit here. In dark heresy grenades blow up your hand more than 1% of the time since it explodes if it jams (a 5% chance) and you roll a 9-10 on a d10 (with a bit of a boost because 6-8 makes you reroll but I can't be bothered to do the exact math) and on the other hand penalties don't stack for jams so the worst you can get is 91-100. This reminds me of a friend who trained for the military who got annoyed at how easily the guns jam since guns tend to jam once out of every couple shots, especially when you're firing a laser. I mean what is jamming in a gun described to have zero moving parts?

I tend to dislike fumble rules outside of automatic failure because it tends to ruin the tone of the scene. Nothing makes a villain less dangerous than falling prone at the end of a charge making him trip and slide on the floor like a slapstick character.

[LordCdrMilitant]

I think you're remembering houserules a bit here. In dark heresy grenades blow up your hand more than 1% of the time since it explodes if it jams (a 5% chance) and you roll a 9-10 on a d10 (with a bit of a boost because 6-8 makes you reroll but I can't be bothered to do the exact math) and on the other hand penalties don't stack for jams so the worst you can get is 91-100. This reminds me of a friend who trained for the military who got annoyed at how easily the guns jam since guns tend to jam once out of every couple shots, especially when you're firing a laser. I mean what is jamming in a gun described to have zero moving parts?

I tend to dislike fumble rules outside of automatic failure because it tends to ruin the tone of the scene. Nothing makes a villain less dangerous than falling prone at the end of a charge making him trip and slide on the floor like a slapstick character.

Lasguns are Reliable. They shouldn't jam often, since they only misfire on a nat 100. The weapon jam is also fixed by a unmodified BS test, so it's also not a big deal when it happens. A best quality weapon never jams.

[Jay R]

I’m fascinated by how many people’s pet peeves are the exact opposite of mine.

My pet peeves include:

• Any “fast” character generation. That’s not a character; it’s a set of abilities. [Yes, I played this way when I started, too – and loved it. But eventually I got into role-playing.]
• One-mechanic systems that try to simulate things with a single mechanic, when the actual actions simulated don’t work that way. [If you are 6 points better in an INT-based skill; that might represent a 30% advantage, and I still might know the single needed fact. But if you are 6 points higher in STR, you will win the tug of war. Using the same mechanic is just bad, bad, bad design.]
• Any game set in an archetype-dominated genre which does not steer characters towards those archetypes.
• Any rules-system that tries to assume the referee/GM/DM is not the final authority, leading some people to believe that all games will be played the same. The GM is the one true defense against stupid rules exploits.

[LordCdrMilitant]

Explain? Do you mean that you want all opposition to have "narrative" health, and did when it's grammatically appropriate?

I too would like HP to go away. It's a relic of battle occurring on the scale of a larger military formation representing an amalgamation of personnel remaining and troop cohesion, that does not belong on the "more detailed" scale of an RPG.


I would like a system where all damage on all things is resolved on a module-basis, and you die when the table says you die. Here's what I would do in my ideal system:

A creature's body would have a hit location table, used to determine where a non-called shot lands.

Then, for each location, there'd also be a damage table, used to determine what the shot does to the target. Damage would apply as modifier to the damage table increasing result severity, Armor would reduce damage, and Penetration would reduce armor. The damage table would range from "Minor Scratch" to "Creature Dies". Most results would impose temporary or permanent penalties on the target. I would keep most of the descriptions mechanical. There'd be a set of general tables for common body parts, and some creatures may have unique tables for special body parts of because of their special defensive qualities.

[Gnoman]

That not only sounds like a potential nightmare to play due to nested table syndrome, but it would be an enormous pain to develop creatures for. The greatest strength of a tabletop RPG is the ease in which you can develop new content, and needing that level of detail for the new monster you've invented would be unpleasant.

[Knaight]

I'm going to try and aim for legitimate pet peeves - tiny little things that really don't matter to overall design, that nonetheless manage to irritate me to no end. It's a short, but pronounced list. Design preferences is a much longer list, and as such will be avoided.

• Variably discrete probability distributions. I don't like "holes" in my die mechanics. Exploding dice that produce gaps around the edges (e.g. 1-5, 7-11, 13-17, etc.) of possible results. The d66 with its 36 results and giant jumps from 16 to 21 and similar annoys me to no end. A multiplicative die mechanic that largely avoids prime numbers (with the possible exception of 2, 3, 5, 7, 11, 13, 17, and 19) and has other gaps is deeply irritating. This irritation persists even when the mechanic works just fine.
• Reporting distances in battlemat/grid units. I don't tend to play RPGs with battlemats that often (deeply spatial board games, war games, and videogames, sure), but for the ones that do reporting ranges on the mat instead of in the fiction is a significant pet peeve. Sure, it's a split second conversion most of the time. In actual gameplay both are being used heavily anyways. Still, I just don't like it.
• Magick. To some extent magick is a synecdoche here, for any number of tiny stylistic things that have no effect on the game, can basically be ignored, and are roughly at the level of a word being spelled slightly differently or a grammatical quirk that just shows up over and over.
• Skill Specializations and Specialized Skills. For all that I adore the Ubiquity system, I do have to throw some shade here. Again, this isn't a mechanical issue - I like skill specializations, and I like specialized skills. The decision to have two different and to some extent opposite mechanics and then give them two names that are almost identical? That's a pet peeve.

[Steel Mirror]

I would like a system where all damage on all things is resolved on a module-basis, and you die when the table says you die. Here's what I would do in my ideal system:

A creature's body would have a hit location table, used to determine where a non-called shot lands.

Then, for each location, there'd also be a damage table, used to determine what the shot does to the target. Damage would apply as modifier to the damage table increasing result severity, Armor would reduce damage, and Penetration would reduce armor. The damage table would range from "Minor Scratch" to "Creature Dies". Most results would impose temporary or permanent penalties on the target. I would keep most of the descriptions mechanical. There'd be a set of general tables for common body parts, and some creatures may have unique tables for special body parts of because of their special defensive qualities.

I've played systems with similar rules, and in fact it was on my own list of pet peeves earlier in the thread. Not to say that those things are objectively wrong, I just don't enjoy them, myself. There a couple things on other people's lists of pet peeves that I personally enjoy in my games, too.

One pet peeve I have is systems that use roll-under and roll-over for different parts of the game. So like, for skill checks say you have to roll a d100 and land UNDER your skill rank to succeed, but when rolling opposed checks you both roll 1d100 and add some number and the higher number wins. Somewhat related, systems that list some modifiers with respect to adding/subtracting from your roll (bracing your rifle gives you -10 to the roll, which makes it easier to hit!) and other modifiers with respect to the TN you are aiming for (if your target is moving, they get -10 to their TN, which makes it harder to hit!) so that I'm always confused where I should be adjusting my numbers and how hard it is to do what I want to do.

[Quertus]

I’m fascinated by how many people’s pet peeves are the exact opposite of mine.

I felt much the same on people's "things that they want to see on other systems". Mine was simply an option, to allow people to create playable simple characters -or- more complex, customized creations. Whereas many other people seemed to want to make all games bad.

Speaking of,

My pet peeves include:

• Any “fast” character generation. That’s not a character; it’s a set of abilities. [Yes, I played this way when I started, too – and loved it. But eventually I got into role-playing.]

One of my "ideal" character creation methods would be to write "Quertus - Wizard" on my sheet, and be done. The sheet is the mechanics, not the character - how much does a starting character need for mechanics?

What, exactly, would you like to see here? Keep in mind, last time we let The Creator try to add mechanics for role-playing, we got alignment

• Any rules-system that tries to assume the referee/GM/DM is not the final authority, leading some people to believe that all games will be played the same. The GM is the one true defense against stupid rules exploits.

Ya know, when I go for a drop in game of Monopoly, I really don't want to spend 4 years getting a masters degree in "this guy's house rules" - I want to just be able to play the danged game. When I bring my Magic deck over to someone's house, I don't expect to have to deal with different rulings for each of my (and their) cards than I'm used to - I expect things to just work.

Now, I have a MtG rule or two that I shove down everyone's throats - whether it's my house or not - to fix a part of the rules that "don't work" (at least not in a casual atmosphere - it "works" (as well as Mew-tew) in tournament level play).

So, I guess my question is, why would you want all the bad that comes with incompatible games, unknown rules, and "rule zero", when the problem you described could instead be solved at the group level, or even by errata from the company?

[Florian]

My pet peeve is fumble mechanics. It doesn't matter how small the chance is - if your own turn can potentially mess you/your party up worse than an enemy's turn through sheer RNG, the game developers screwed up. Period.

Splittermond actually makes good use of a fumble mechanic. The core mechanic is 2d10+mod vs DC, failures happen on twin ones. You can always opt to make a save roll of 1d10+mod, completely negating the fumble chance or you make a risky roll of 4d10+mod for higher chance of success, but also higher chance of fumble. That's overall a pretty good risk vs. reward mechanic.

[Zombimode]

Most versions of D&D. I think 2nd edition actually had 3: THAC0 for combat, percentile dice for thief skills, and roll-under ability checks for proficiencies. Some versions use a d6 roll for skills. Do you consider ambushing and/or detecting an ambush to be a skill? That's a fourth mechanic for surprise/being surprised, but they didn't consider what would happen if a good ambusher tried to ambush a good ambush spotter (they only cover good skill on one side and default skill on the other)

For what it's worth THAC0 and roll-under ability checks are not really different mechanics. Or rather: they are different only in the sense that THAC0 and 3e style attack rolls are different. All These mechanics conform to the 3e core mechanic: 1d20 + modifieres compared to a DC. THAC0 and roll-under just obfuscating this.

Percentile thief skills are different because they are more granular. Ambush rolls are less granular.

Concerning ambushes: thats not true, from what I remember. There is a baseline for ambushes (ambush happens on 1-3 on d10, iirc). Then there are creatures that are better at ambushes. Usually this is confusingly described in absolutes ("Tigers ambush their prey on 1-2 on d10..."). Then there are creatures that are apt in avoiding ambushes, also confusingly described in absolutes ("Halflings are only abushed on 6-10 on a d10..."). Ignoring the confusing description those are just modifiers to the baseline DC of 3: if a Tiger wants to ambush an Halfling a roll of 3 + 3 (Halflings "ambush spotting" skill) - 1 (Tigers "ambusher" skill) = 5 on a d10 is needed.

[Guizonde]

I think you're remembering houserules a bit here. In dark heresy grenades blow up your hand more than 1% of the time since it explodes if it jams (a 5% chance) and you roll a 9-10 on a d10 (with a bit of a boost because 6-8 makes you reroll but I can't be bothered to do the exact math) and on the other hand penalties don't stack for jams so the worst you can get is 91-100. This reminds me of a friend who trained for the military who got annoyed at how easily the guns jam since guns tend to jam once out of every couple shots, especially when you're firing a laser. I mean what is jamming in a gun described to have zero moving parts?

I tend to dislike fumble rules outside of automatic failure because it tends to ruin the tone of the scene. Nothing makes a villain less dangerous than falling prone at the end of a charge making him trip and slide on the floor like a slapstick character.

dark heresy, perhaps you're right. lordcmdrmilitant will know more about that, they seemed pretty knowledgeable about that system from previous posts. i only rifled through the rulebook, and i'm currently playing rogue trader. the stats for hellguns and autos are legit for rogue. the low low bar for jams comes from whfrp2e, and that i know due to unfortunate circumstances. in rogue trader, the dm pulled out the rulebook due to the table's disbelief at the natural one mechanic. it's a short paragraph but it's in there, and the silliness is too good to pass up. might be an alternate rule, but i remember reading "natural 1 = automatic success no matter the degrees of success".

finally, the "+2/-2" mechanic is indeed a houserule for my pathfinder game, and it works great, or should i say a lot better than pf's usual nat1 failure mechanics. i was throwing it out there so other people might benefit from it.

i realize mixing up 4 systems together in the same post was very unclear, my bad.

[Tanarii]

Unnecessarily complex rules to resolve anything. The worst offenders I've played and run are Gurps and Shadowrun. The worst I've merely read but not played or ran is Burning Wheel (including Tocherbearer).

Those GM sections that talk down to me and tell me how to "do it right".

Yup. Especially bad are Kevin Siembieda (Palladium/Rifts), Erick Wujcik (Amber DRPG & Paranoia, but also cofounder of Palladium) and Luke Crane (Burning Wheel).

Siembieda and Wujcik occasionally approach Forge-level talking down. Crane is a product of the Forge, so it's hardly surprising in his case.