Bumper sticker ???

I've often wondered what makes people choose certain bumper stickers and think, "Holy crap, I need that on my car." I'm for them they totally crack me up, but saw one this afternoon that just really got me wondering. The one I saw was across the whole back window of the car and said "Go Eff Yourself." Except, it wasn't my pc version...WHAT THE CRAP!?! Now, sometimes we all might think that phrase or even say it, but really saying it to everyone that drives behind you...I'm just baffled.

Any who, peace...