Here's something that drives me up the wall.
Go to your favorite mall, movie theatre, bar, wherever. When you're in the can, look around. More often than not, someone will finish taking a leak or a poop, and head straight for the door.
I mean really. If I wanted to touch these peoples' genitalia, I would ask them.
Support the hand-washing movement! Give this person a stink palm, tell their girlfriend or boyfriend how revolting their significant other's hygene is, do something!
Stand up for your right to not come into contact with leftover excrement!