Someone once said "We will remain the same until the pain of remaining the same becomes greater than the pain of the change."
Some people are very comfortable where they are, and in one way or another, choose to stay there. Bill Harris talks about thresholds - some people have much lower thresholds than others - and it's when we raise our thresholds that we grow. If I look at it that way, does having a lower threshold or a higher threshold make a person better than the next? I don't think so - we're all just different.