What would you write on the inside of a public bathroom door?

Question:

What would you write on the inside of a public bathroom door?

I'm curious, what would you write on the inside of a public bathroom door. It can be anything, preferably in English, but if you have a great line in your own language, tell me.

Best Answer - Chosen by Asker:

The toliet is a bomb and if you sit on it you will blow up.