On the train, a mother and son were sitting together. At dusk, the mother and son began to fidget, while the son stared with his face flat against the windowpane. I asked the child who has been watching, is there something going on? His mother smiled embarrassedly at me, and the child turned around and said to me that his father was a train driver, and he had not been home for almost a month. Today is his father's 45th birthday. He and his mother wanted to give him a birthday present, so...