stacey, If you have never seen this, then you have been fortunate. I think public transport does tend to bring out the worst in a lot of people, as they think they have a captive audience who will listen to them.
I used to work in central Croydon, travelling on the train to Wimbledon, and then the tram from Wimbledon to Croydon, and pretty much every day there was some sort of anti-social incident on the journey. It was bloody awful and I couldnt wait to finish the contract.
There are a lot of racial and social problems in Croydon and a few of its surrounding areas.