He didn't like nuns.
A roamin catholic
She was taking god's name in vein.
Thought of this one on my own while playing WoW a couple days ago and I'm pretty sure it hasn't been told before. I like corny jokes. I Googled it and didn't find anything (:
Because the girls always cling on him afterwards.
Because the black kids don't wanna get kicked off the basketball team.
When he stands next to your girlfriend and says her hair smells nice.
Nun
Force of habit.