"What gives expertise its power is not just the sheer amount of information stored in a brain, but the way it is organized. This is the product not of "talent," which is mere potential (and every brain is packed with that), but of intense motivation -- fascination, obsession -- driving long, hard work. And motivation operates in a feedback loop: the pleasure of difficult success feeds the drive for more such challenges and rewards. It's easy to see that the reinforcing rewards are both internal -- the aesthetic rush of solving a problem -- and external: praise, status, opportunity."
-http://ambivablog.typepad.com