Fluff vs. Mechanics

[sithlordnergal]

I'm curious, how important is fluff to all you players and DMs out there? And by fluff, I mean things that are stated but have no mechanical detriment or benefit, they're just things assumed by a given book.

A good example would be the "Druids won't wear metal armor due to it being taboo." There are no mechanical detriments for a Druid that chooses to wear metal armor like in 3.e. By RAW, the Druid loses nothing, and as such it is on the DM's head to make a penalty.

Personally, I see fluff as a guideline that can be tossed out without any real concerns. That Demon over there? Could be a lawful good Paladin. The Druid in metal armor? A few druids might give them the stink eye, but they're fine. Some broad assumption about a race? Feel free to break it.

My only rule as a DM is find a way to justify it. You're a Dwarven Druid that served in the Dwarven Army? Go ahead and wear metal armor. Dwarf Druids will have no issue with it, but other Druids might.

EDIT: So, in order to clarify things more, the Druid thing is just an example. Other examples could be height and weight. Does it matter to you, as a player or DM, if a person brings an 8 foot tall Dwarf. There's no mechanical benefit, you're still a Medium creature, you're just a Dwarf that's as tall as a Goliath. Or how about a peaceful Barbarian, one that prefers peaceful solutions and never does lethal damage? It goes against the fluff of being a Barbarian, but there's nothing stopping a player from doing so.

As a person who frequents the forums, I have seen a few DMs who would balk at the idea of an 8 foot tall Dwarf, because it goes against the established norm. So, how important is that sort of thing to you?