My pet peeve is players who choose their character's race purely for the stat boost and then proceed to play them as nothing more than "humans with funny ears". IMO even if you're playing against type (say as a dwarven wizard) you should still be trying to play against type in a
dwarven way. (In the same way at ST_TNG's Worf was very much against the Klingon norm, and yet he was still very distinctly Klingon for all that.)
However, when it comes down to it, it's the
player's character, so if that's what he wants to play then so be it.
I despise consistently late players.
Probably the one thing that most annoys me is the player who is consistently late or simply no-shows... and especially the one who fails to let the rest of the group know when that's happening. I get that occasionally stuff happens that will make a person late or unavailable, and indeed that that will occasionally happen at the last minute.
But in a world with the internet, email, and mobile phones there are very
very few reasons good enough to justify failing to let someone know.
The worst example of this occurred at a game I'd had scheduled for a while where (due to seating) I had a limited number of spots and so had had to turn people away once the game was filled. And then one of the players simply didn't show up without
any word at all. And so we ended up playing with an empty chair and a disappointed waiting list.