A mechanic was removing the cylinder heads from the motor of a car when he spotted the famous heart surgeon in his shop, who was standing off to the side, waiting for the service manager to come to take a look at his car .

The mechanic shouted across the garage,” Hello Doctor!! Please come over for a minute.” The famous surgeon, a bit surprised, walked to the mechanic. The mechanic straightened up, wiped his hands on a rag and asked argumentatively, “So doctor, look at this. I also open hearts, take valves out, grind them, put in new parts, and when I finish, this will work like a  new one…

So how come you get the big money, when you and me are doing basically the same work?”

The doctor leaned over and whispered to the mechanic…

“Try to do it when the engine is RUNNING”