I've been reading Daniel Pink's Drive, which has turned out to be a great book about how to motivate ourselves and others. One point that stuck out to me is where the author describes mastery as an asymptote, an algebraic concept in which a curve grows increasingly closer to a straight line, but never quite reaches.
Pink explains that this idea is difficult to accept, because we tend to get frustrated and give up if we aren't able to be perfect at what we are attempting. Understanding that this is normal, however, can help us set proper expectations and avoid becoming discouraged as we seek to master different skills in life.