"In some moods, or for some people, the desire to improve can seem so natural as to be banal. The impulse drives forward so much in our culture that it can color our thoughts and shape our actions without being much noticed. But in other moods, or for other people, this strenuous desire becomes all too noticeable, and its demands crushing. It can then drive a sleepless attention to ourselves, a desolate evaluation of what we have been and what...