This mostly pertains to online play, but to me the worst habit a player can adapt is complain every single time they lose to someone else. The reason this really grinds on my nerves is because the complaining is usually the result of the player having the gaming version of a "God" complex, in that they believe they are the best thing ever to hit the game and the only way someone else can bring them down is if they use some kind of cheap strategy or hack the game somehow. Haven't you guys ever stopped to think that maybe you lost simply because you aren't as good as the other player?