Zinedine Zidane's headbutt (w/ video) 5

An unfathomable action given the state of the game, what was a stake and the fact that this was going to be Zidane's final career game. At that point in your career you should have quite a thick skin for any insults that might be said on the field, and the maturity to deal with intense situations and to think of everyone else who's also at stake; in Zidane's case, not only his team but his entire country depended on his actions that day. He let everyone but Italy fans down.