Reloading even if I only fired two shots. Going out of my way to steal enemy vehicles or simply prevent them from using it. Pissing someone off with my "unfair"/aggressive play style. Winning by any means necessary on fighting games (usually goes hand and hand with the above part) also results in them crying 'cause I hit their dumbass off of the stage (Soul Cal V scrubs). Getting too into it when controlling a vehicle (especially jets on BF3 or when playing racing games).