good ambition, bad ambition

This is from my latest read of Dave Harvey's Rescuing Ambition, which is a great book and easy to read. In it he quotes from C.S.Lewis, one of my favorite authors:

Ambition! We must be careful what we mean by it. If it means the desire to get ahead of other people... then it is bad. If it means simply wanting to do a thing well, then it is good.... What we call "ambition" usually means the wish to be more conspicuous or more successful than someone else. It is this competitive element in it that is bad. It is perfectly reasonable to want to dance well or to look nice. But when the dominant wish is to dance better or look nicer than the others--when you begin to feel that if the others danced as well as you or looked as nice as you, that would take all the fun out of it--then you are going wrong.