Not all good things make us feel lucky. For example, we enjoy sports with an unspoken sense of entitlement. We have given so much of our lives and so much emotion to it that we feel we deserve the joy of it all. Some athletes are just as good as they are. This moment makes me feel lucky to be living in this era. That’s what Roger Federer did for millions when he ruled. On Thursday he announced our luck had run out. He had quit playing professional tennis.