Why do people act so stupid?

I wonder why do people act so stupid. Is it in their DNA? Or rather their environment? I don't know; but what I do know is this: it is better to know whether or not to be stupid or just act stupid. For me I just act stupid because people (I mean mostly the hot guys LOL) tend to help you out more and they sometimes ( not all the time) sympathize with you alot more. But I am alas married to the man of my dreams (sometimes LOL); when he's not acting like a one of our babies (LOL). The reason why I ask about the stupidity is this: there are alot of people who live in Florida that are really dumb asses (LOL): for example my cousin in law here's what he did: he gave the cat a bath and then cut off all of her whiskers. I mena come on now, you DONT cut off a cat's whiskers. The whiskers help the cat see at night and keeps them balanced and now the poor cat is off balanced (LOL, funny but not so funny). Well alas that's all I got to say for the moment, I will write some more later.