Mechanic and Surgeon

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 waiting for the service
manager to come take a look at his car.

The mechanic shouted across the garage, "Hello Doctor!
Please come on over here for a minute."

The famous surgeon, a bit surprised, walked over to
the mechanic. The mechanic straightened up, wiped his
hands on a rag and asked argumentatively, "So doctor,
look at this here. I also open hearts, take valves
out, grind 'em, put in new parts, and when I finish
this will work as a new one. So how come you get the
big money, when both of us are doing basically the
same work?"

The doctor leaned over and whispered to the mechanic
"Try doing it with the engine running."