A mechanic was removing the engine parts from a motorcycle

A mechanic was removing the engine parts from a motorcycle. When he saw famous heart surgeon in his shop, he called the surgeon and said, "Look at this engine. I opened its heart, took the valves out, repaired and put them back"So why do I get such a small salary and u get such a huge sum?
The doctor smiled at the mechanic and came close to his ear and said, “Try the same when the engine is running.” :slight_smile: