The Taunt button in Street Fighter 4.
People go absolutely ballistic when you during a dizzy or a combo, really throws them off their game. I got so many "Poor Sportsmanship" ratings on my GFWL profile for using taunt in Street Fighter. Look, if they didn't want us to use it, they wouldn't have it in the game, and they certainly wouldn't give each character like 20 different taunts.