Comment by iamwithnail

This is the mechanic story all over: Guy takes his car to a garage because it keeps breaking down, and the mechanic leans in and listens to the engine for a minute. He goes and gets a hammer and listens to the engine again, and then raps sharply on the engine casing. The engine goes back into sync and stops breaking down.

The mechanic says "that'll be £500, please." The guy's outraged: "But all you did was tap it!"

Mechanic replies "it was a pound for the tap, and £499 for knowing where to tap."

Edit: Crap, beaten to it.