Teenagers in particular tend to have an inbuilt compulsion to develop skills. Teenagers will spend hours upon hours of their spare time improving their skill level at sports (including skateboarding), musical instruments, video games--whatever grabs their fancy. Even if you lock them in a windowless room with 60 hours of homework, they'll still get really really good at doing those pencil-spinning tricks with their fingers.

I think it's a natural part of the human psyche. If you read about the Mongols or the Comanche or some other horse-nomadic culture, the one thing you learn is that they are really really good at horse archery. As in: virtually every adult male Mongol or Comanche could accurately perform archery from horseback, at full gallop, while hanging from the horse sideways to shield their body and firing arrows from underneath the horse's chin. How is that possible? Well, if you grow up as a Mongol boy, once you reach the stage in life where a Western kid might get a skateboard or a guitar or whatever, you have horses and bows, and all the older kids can already do that stuff.