Output Stream of Consciousness

Over the past few years, on the buses I take to work, I've noticed more and more that teenagers seem very, very attracted to standing or, in some cases, even huddling by the bus exit. In many cases, it's not even a matter of lack of available seating. As I get out fairly early on most of these routes, I notice that they move rather unwillingly, not usually all that much to my detriment, but they regularly get hit by the doors.

I must admit that I'm puzzled.

I haven't worked up the courage to ask them why.

In some cases, it's obvious. Three people standing together by the bus exit is just an easier way to make conversation between three people.

Other times, though, you wonder. Are they afraid to sit with other people? Did they have a traumatic experience once from missing their bus stop because of people in the way? Is there some need some of them have to shrink into a corner? (That possibility makes me sad) Are they just afraid of touching people for the inter-bus-stops journeys?

I wish I knew. Not knowing is driving me crazy :)