One of my father’s favorite sayings is “Tennis, chess and war are lost through one’s own mistakes” (translated from German). Growing up, I used to really dislike this saying, in retrospect mostly because I lost against my Dad at tennis for a long time excactly because of my own mistakes. Yesterday afternoon, I took the kids to the US Open to see some of the first and second round matches on the side courts where you can sit right up close. All afternoon there was only one instance of a player...