"Oh No You Didn't"

It grinds my gears when I hear someone say "Oh no you didn't!" What's up with that? The statement is usually a response to something that obviously did happen. It clearly happened, why deny it? It is mostly spoken with a cocky in-your-face attitude. Like, "I'm so cool, I can negate that action that you just performed." It's stupid and pointless and it grinds my gears.