When you nail your nutsack to the pool table at the pub and forget you were wearing your spiderman undies.

When you get drunk at Christmas & piss over the end of the verandah like you always do and forget there is a flashing LED lit santa on the lawn set to go off every five minutes - just as the church bus pulls up full of kids.

When you've given the Jehovas witnesses a bunch of hash cookies and they come back later because they forgot their bible. They get really pissed off when they see you burning it to start the BBQ.

I've got some really embarrassing ones too, but I only talk about them when I'm drunk.