It's easy to find something to get angry about while driving, but the laughs are few and far between unless you account the times when you sarcastically laugh at the other drivers' crappy driving skills.
This lack of laughs is exactly why bumper stickers are a crucial part of our automobile dependent lives, for the laughs they provide help prevent road rage incidents by keeping the mood light.
Of course, there are a ton of bumper stickers out there that are meant to make other drivers angry, but it's best to just think of those as markers indicating which cars should be trashed in the parking lot!
See If None Of These Bumpers Stickers Make You Laugh, Nothing Will here