One night a burglar, needing money to pay his taxes, decided to burgle a safe in a mom and pop grocery store.
On the safe door was a note that read “Please don’t use dynamite. The safe is not locked. Just turn the handle.” He was quite pleased with this turn of events so he followed the instructions.
Instantly a heavy sandbag fell on him, the entire store was floodlighted, and alarms started sounding. As the police carried him out on a stretcher, he was heard moaning: “My confidence in human nature has been terribly shaken.”
If your car’s engine develops a knock, chances are it’s opportunity knocking for some mechanic.