As a very young child, I never missed an opportunity to strike up a conversation with a stranger. Since my family didn't have a lot of money, I rode the bus often. Everyone on the bus is going somewhere... so that's an easy conversation starter. Eventually my mom had to implore me to stop talking to everyone, and stop giving out personal information. I was being way too trusting. It actually felt weird for a while to walk past people without trying to talk to them. That might have been the first step toward introversion, but I don't think it's the cause or anything.
I think everything changed in middle school. I never had much of a problem getting along with children in my elementary school, but in middle school the popular boys had a mean streak to them. They were basically bullies whenever they thought they could get away with it, and they didn't like being stood up to. I remember rescuing a kid from being pushed out of the locker room in his underwear (as I had the size and confidence to do so) and these bullies asked me why I cared, since they weren't doing it to me. I was pretty good at sports, but there was no way I was going to spend more time with that kind of kid than I had to.
At the same time, I was getting frustrated with the pace of learning in my math and science classes. In 6th grade I had the realization that I was smarter than my math teacher. The same was true in 7th grade. I was annoyed that the school did nothing to accommodate me.
So the well-liked kids were jerks, and the adults didn't seem to care about kids like me. By the time I entered high school I was firmly committed to a counter-culture mindset.
