Mechanic & a Heart Surgeon

A mechanic was removing a cylinder head from the motor of a Harley
motorcycle when he spotted a well-known heart surgeon in his shop.
The surgeon was there, waiting for the service manager to come and
take a look at his bike. The mechanic shouted across the garage,
"Hey, Doc, can I ask you a question?"

The surgeon a bit surprised, walked over to the mechanic working on
the motorcycle. The mechanic straightened up, wiped his hands on a
rag and asked, "So Doc, look at this engine. I open its heart, take valves
out, fix 'em, put 'em back in, and when I finish, it works just like new.
So how come I get such a small salary and you get the really big bucks,
when you and I are doing basically the same work?"

The surgeon paused, smiled and leaned over, and whispered to the
mechanic... "Try doing it with the engine running."

(Source: Unknown)