A guy tells his psychiatrist, “I always have this weird dream at night. I am locked in a room with a door on which there is a sign. I try to push it with all my strength, but no matter how hard I try, it won’t budge. “
The psychiatrist muses, “Interesting. “But tell me what does the sign on the door say?
The guy replies, “It says ‘Pull’“.
This joke is included in the Black Book of Jokes. You can order it from here.