The heart surgeon was having his car worked on at a garage.
The mechanic knew him, and said to him, “You see this car I’m working on? Well, when it came in here, the motor was frozen. I cleaned it up, lubricated everything in it and now it’s purring like a cat. So, you see Doctor, you and I do the same work.”
The surgeon answered, “Try working on it while it’s still running.”