Where does sense of humor come from?

Where do we get our sense of humor? Everyone's is different. It can't be genetic; my parents look at me like an idiot at least half of the time I'm laughing hysterically at something. It can't all be social either; I have several friends who actually think Dane Cook is funny. It's one of the most individualized traits in each person, and I want to know where it comes from?

I wonder when the first time I saw someone fall was. It must have been freaking incredible, because I think that's the funniest thing in the world. I can picture little baby me riding along in a stroller witnessing some jogger in spandex shorts and a fanny-pack tripping over a curb, landing on his face, smushing his mustache, and breaking his aviators. Little baby me apparently thought this was fantastic and filed it away into the part of the brain that deals with intense pleasure and under the tree labeled "funny".

On that same note, where does one's laugh come from? Just like sense of humor, everyone has a laugh that is uniquely theirs, and I feel that how a person laughs says a lot about them. A reserved and shy person might have quiet little mouse laugh to avoid being noticed for fear they weren't supposed to be laughing at all. A more outgoing person might have a loud and gregarious laugh that fills a room and draws the attention of every eye. An annoying person might have a weaselly whinny that embodies their very being, and a shrew of a person always seems to have a shrill cackle that sends shivers down your spine.

Laughter, to me, is one of the most attractive qualities of another person, both what they're laughing at and how they're doing it. When I think of my best friends, I hear their laughter. All of them have good, strong, hearty laughs. The same is true with members of the opposite sex that I find myself attracted to for any extended period of time. She might look good and seem cool, but if I don't dig the laugh---that's a deal breaker, ladies.

Ahh, well... off to watch some internet videos in hopes of laughing hard, outloud, by myself, at my computer screen.