I met a lunatic in George street while waiting for some friends. He hung around outside of Planet Hollywood, telling people he was going to marry a movie star and showing off his nonexistant muscles. He seemed to calm down when he found someone to talk to.
The other day on a crowded train I saw a young female drug addict sit prowling up and down the carriage. She sat down next to a woman and start harassing her - asking for a fight. The girl threw a punch at the woman. The woman grabbed her umbrella and started bashing the girl over the head. The girl ran off the train. The woman claimed she was nearly a blackbelt in tai kwan do, and regretted that she didn't get off the train to fight the girl. The girl sitting next to me said "oh no she did it again". I wonder if this is a regular occurrence.
I saw the same girl again a few days later talking to her friend. The old couple sitting opposite her were relieved when she left.