Someone who thinks they are the best at a game, be it of the video, computer, or card/board variety. When someone with this syndrome loses a game, or is losing they call you a cheater and yell and curse at you. Seeing how they think they are better than everyone else at a peticular (or all) games.
"Damn This Game, it cheats I swear!" "It doesn't cheat, you just dont know how to play well enough. You Ußerleetness Syndrome headed fool."