Math saves lives
A math professor was explaining a particularly complicated calculus concept to his class when a frustrated pre-med student interrupts him. "Why do we have to learn this stuff?" the pre-med blurts out.
The professor pauses, and answers matter-of-factly: "Because math saves lives."
"How?" demanded the student. "How on Earth does calculus save lives?"
"Because," replied the professor, "it keeps certain people out of medical school."