A pre-med student was required to take a difficult class in physics. One day the professor was discussing a particularly complicated concept. The student rudely interrupted to ask, “Why do we have to learn this stuff?”
“To save lives,” the professor responded quickly and continued the lecture.
A few minutes later, the same student spoke up again. “So how does physics save lives?” he persisted.
“It usually keeps idiots like you out of medical school,” replied the professor.