"Don't throw hats on the roof"
It's kind of an obvious sign, but I want it in front of my office. On the roof? Hats, several of them. Encouraging people to break the rules of society and throw your hat on the roof! If there is a volunteer helping out front of the office and they see someone trying to throw their hat, the volunteer would stop them from doing so by using a stern voice and a well pointed finger. Why? The hats would be donated to charity, but the fun of breaking the rules and standing up to the man! It's good for the soul.