No one will ever know why people constantly do the following things:
1. Cut you off just to wait at the same red light.
2. Ride your *** and think that it will make you move faster (speeding is bad)
3. Honk their horn at you when you are waiting for someone to cross the cross-walk. What do they want ya to do, hit someone (for crying out loud)
There are more things but those are the top three I believe.