The Opposite of Tragedy

The title of this post is the basic summary of the book I'm reading: Time's Arrow. The general story follows a passenger living inside Tod Friendly. Tod is living his life in reverse, and the passenger can't really make sense of it. In some aspect, everything around him is a tragedy. Poop goes back into people, doctors pay people to hurt them, and Tod steals candy from babies for some quick cash. However, as this is the 2nd time I've read this book, I know how it ends. It leads up to one event in history where reversing things is actually good: World War II. The transition of living a new life as unsatisfied doctor under a fake name to helping people who had nothing (plus getting a hot, young wife) makes this the opposite of tragedy.