In elementary and middle school I kept to a small group of friends. We had small grades then and everyone else was a waste of time, too stupid or too much of a prick/bitch.
Once I hit high school, where the class of 2014 has about 300 people, I have maybe about 10-15 friends, way more than the old 3-6. I'm fine with that, I don't want to be friends with too many people.
It's not some people's fault that they have trouble branching out or making social connections. Some kids were raised without proper social skills, and some of them are just totally out of today. I know one guy at school who's all big into like Nintendo and all that still, and always talks like 100% perfect English online. He still somewhat manages an okay friendship with people as far as I can tell.