Heart Surgeon vs. Mechanic

In a car garage, where a famous heart surgeon was waiting for the service manager to take a look at his Mercedes, there was a loud mouthed mechanic who was removing the cylinder heads from the motor of a car. He saw the surgeon waiting and lured him into an argument.

He asked the doc after straightening up and wiping his hands on a rag, "Look at this car i'm working on. I also open hearts, take valves out, grind them, put in new parts, and when I finish this baby will purr like a kitten. So how come you get the big bucks, when you and I are doing basically the same work?"

The surgeon very calmly leaned over and whispered to the loudmouth mechanic, "Try doing it with the engine running."