A policeman pulled over a car, walked up to the driver's window, and asked the man if he knew why he was pulled over.

"No," the man replied.

"You failed to stop at the stop sign," the officer explained.

"But I did slow down!" the guy argued.

The officer shook his head.  "You are required to stop.  That's why they're called stop signs."

The man started to get belligerent.  "Stop, slow down -- what's the difference?"

The officer pulled out his baton.  "I can show you.  I'm going to start hitting you with my baton.  You tell me if you want me to stop or slow down."