Any incarnation or variation of "All Alliance are dumb" or "All Hordies suck". Yes, okay, it's in character to not be fond of the guys you're presumably at war with, but a) people who say this usually don't give a crap about being in character and b) it really bugs me when people make blanket judgments that everybody who plays an is an idiot.
Also, on a more pointlessly nit-picky note, gratuitous and improper use of the term "noob". Person A will generally call Person B a noob whenever Person B does something Person A doesn't like (which is true of any insult, really, but bear with me here)--for example, headshotting him with a sniper rifle. Calling somebody a noob when they're clearly GOOD at the game is ridiculous and makes no logical sense. ...As is expecting people to be logical when they're mad, but shhh. >.> <.<
I used to play an MMO called Dark Ages, and one of my characters was a priest of a certain temple. I once kicked another player out of the temple for being disrespectful. Said player then proceeded to get bitchy and call me a noob. I'd been playing that game for two years, since beta. Who's the noob, again? XD
