Physician

A woman was in her physician's office when she suddenly asked him to kiss her

He replies, "I can't, that would be against my code of ethics" Twenty minutes went by and the woman again pleaded for him to kiss her. Once more he refused, explaining as a doctor he simply could not. After another 15 minutes passed, the woman begged him again. "Look, I'm sorry. I just can't kiss you. In fact," he sighed, "I probably shouldn't even be fucking you."

I asked my physician why he hits people on the knee with that little rubber headed hammer

He said "just for kicks"

What’s the difference between a physicist and a physician?

A physicist is busy before firing a catapult; the physician is busy after.