Loneliness is a curious thing. Most of us can remember feeling most lonely when we were not in fact alone at all, but when we were surrounded by people. Everyone has experienced, at full of happy laughing people. It suddenly seems to you as if everybody knows everybody else, everybody knows what is going on everybody, that is, except you. This feeling of loneliness which can overcome you when you are in a crowd is very difficult to get rid of. People living alone are advised to tackle their loneliness by joining a club or a society, by going out and meeting people. The passage is mainly about______.