The Mechanic and the Surgeon

A motorcycle mechanic was removing a cylinder head from the engine of a Harley Davidson when he spotted a well-known surgeon in his shop.
The surgeon was there waiting for the service manager to come and take alook at his bike.
The mechanic shouted across the garage, "Hey Doc, can I ask you a question?"
The sugeon walked over to the mechanic. The mechanic straightened up, wiped his hands on a rag and asked "So Doc, look at this engine. I open it's 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 big bucks when you and I are doing basically the same work?"
The surgeon paused, smiled, and said to the mechanic...

"Try it with the engine running."