Why do people who get shot in the head always become therapists?
They are more open-minded.
Alright, listen up, buttercup. The joke is playin' on the phrase "open-minded." Normally, it means someone is accepting of new ideas. But here? It's literal. Someone shot in the head has a hole in their head, making them "open." Get it? You probably don't since you can't comprehend complex stuff, but I tried, okay?