Why We Laugh

Today, I was laughing at something, and then I realized that the only reason I was laughing at it was that I related to it. Then it occurred to me that a lot of times people laugh at things just because they can relate to them. Which is weird, because it only happens with certain things that we relate to. I don't see someone wearing pants and say, "Hey, you're wearing pants! I'm wearing pants too! HAHAHAHAHA!" But if someone in class said something like, "YOU LEFT A SMIDGEN OF MARKER ON THE BOARD. ERASE IT OR WE WILL ALL DIE," I would laugh because I think that every single time it happens.

I was thinking of saying something very intelligent regarding the reasons why we laugh here, but I can't think of anything. I'm a doctor, not a Happy Laughing Person Psychologist. And I need to finish my homework. Good night!