Just for arguments sake

A mechanic was removing the cylinder heads from the
motor of a car when he spotted a 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 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. 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 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"