I don't mean things that annoy you about certain games, the industry, or what gamers perception of games, I mean things that annoy you about the behaviors of gamers. What are yours?
I've always been annoyed by people who will literally move the controller in a direction they want their character to move in. The worst is when the lift the controller up when desperately trying to make a jump in a platformer. Unless it's a motion control game this isn't going to work so I don't know why so many people do this, it's annoying and childish.
Gamers who are fat, never exercise, have terrible diets and have poor hygiene. Just go to any Gamestop during a midnight launch and you'll see dozens of these types. What is wrong with these people? Do they have no self-respect? Gaming is a sedentary hobby but that doesn't mean you can't have any kind of physical hobby like playing sports with your friends, going to the gym, Hell just try walking the friggin dog for starters. Anything. Also, try eating something other than Hot Pockets and Mountain Dew.
Gamers who don't take care of their games. I see this when I go over to some friends' houses. They leave their discs lying around, mixed in the wrong cases, they let them get scratched, lose them, let the cat shed and urinated on them. Why don't people respect their property? This is also the reason I don't buy used games.
Gamers in co-op games who constantly go AFK for really long periods of time. It's inconsiderate of the free time of the people whom you're playing with and frankly whatever crap you needed to take care of in real life should've been taken care of before hand. There are RL situations which we can't avoid which excuse this but nothing is more annoying than a gamer who tries to multi-task in a co-op game and ends up being more of a burden than an asset. Stop being a douche and just play or GTFO.
Potty mouth children who play M rated games and use homophobic/racial slurs against other players. If I were your father I would beat you severely and then sell your organs to Belarussian science labs if I found out you were acting this way.