he knows he's human too

Im on a tram with an angry man who has a screw loose. he is taking to himself. shouted at me for using my phone. and grumbles at the tram to go faster. just two minutes ago however, he looked up at another old man who was getting off the tram and said to him'have a good day son.' and what i found most remarkable was when theold man in his early sixties turned around and saio'thank you sir.'