4. Rage Quitting
Alright, nobody likes getting their ass handed to them in an online game, but hey, it's no big deal - just relax, take your beating like a man, and then wait for the game to end so you can leave the lobby with your head held high (sorta). Too many people - especially youngsters - however have no grasp on this concept, and will simply rage-quit, which means getting in a huff and then promptly leaving the server or, in extreme cases, just shutting the console off and stopping play completely. We've all had our irate gaming moments, but all it does is prove that you're a sore loser, and it will irritate the opposite team, because if you leave, it's likely other players will, making the game de-evolve into a lopsided mis-match, which might eventually be forfeited if the entire team rage-quits (which I've seen happen far too many times).