I was about 14 and was going to stay with my friend in Buckinghamshire. I had to go to Uxbridge on the Metropolitan line where she would meet me. I got on the train at Baker Street and, after seeing the doors opening the same side at every one of about five stations, I put my case against the doors the other side - the train was packed - and sat on it. Well, at Uxbridge, didn't the doors just open my side? I fell out backwards on to my case on the platform, legs all over the place and there she was at the ticket office howling laughing. Thirty odd years later I still haven't got over that.