Sadly the answer to that question is the fact that humans tend to follow and integrate with people similar to themselves. It happens in the animal kingdom all the time, and we tend to follow suit. The trouble lies with the fact that if someone is just slightly different, we as humans pick up on it and use bullying tactics to push them out of the 'pack'. a bit like the runt of the pack in wolves. The strangest thing is that those people who follow like sheep tend to be sheep for their lives. On the other hand the 'different' or unpopular teens tend to have a unique personality that makes them go on to be successful. Not only because they have learned to do things on their own, but their capabilities stretch much wider than the 'sheep'. They learn to think for themselves, and more importantly learn that they don't have to listen to someone else giving directions especially if that person has a lower IQ.