Speech and Debate kids, usually. They formed the basis of a lot of my interactions with other people my age when I was in high school. Maybe I got the intellectual cream of the crop. There are plenty of stupid teenagers in that age group, but I find the better ones tend to be clustered around 17 years old. It was at that age that they actually really wanted to do a good job so they worked hard and produced relatively quality material, instead of either just making dumb, incompetent crap like younger teenagers, or cynically tailored pandering like older teenagers.