An auto mechanic was removing a cylinder head from the motor of a BMW M3 when he spotted a well-known cardiologist in his shop.

The cardiologist was there waiting for the service manager to come and take a look at his car when the mechanic shouted across the garage, "Hey Doc, want to take a look at this?"

The cardiologist, a bit surprised, walked over to where the mechanic was working on the BMW.

The mechanic straightened up, wiped his hands on a rag and asked, "So Doc, look at this engine. I opened its heart, took the valves out, repaired or replaced anything damaged, and then put everything back in; and when I finished, it worked just like new. So how is that I make $20,000 a year and you make $500,000 when you and I are doing basically the same work?"

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