When the GM sighs Key Ring

Roleplaying games (such as Dungeons and Dragons) are generally cooperative; everyone works together to accomplish their goals, to create a fantastic adventure story, and to have fun. But while that may be the theory, in real life a certain adversarial attitude tends to develop. One too many of the game master's carefully crafted encounters is wiped out by a clever or devious ploy by one of the heroes, one too many NPCs hosed the players, and suddenly there is an undertone of one-upmanship and petty mind games. Finally, the players get to the point where irritating the GM is as much a goal as gaining a level is. And when the GM sighs, that means we win!