I can't imagine anything more satisfying than seeing the face of a fifteen-year-old light up at the realization that she can make some ordinary chord progression sound like the best idea in the world by noticing how the overtones mix and letting her fingers respond on the piano.
It is the light of artistry. It is mastery. It is, to be sure, fleeting because the girl does not spend hours at the piano. But it is an experience that never comes to many young people who do spend those hours at the piano because their hearing has become jaded with too much external product and not enough inner awareness.