Oveheard on the train

The things you hear on the train sometimes mundane, but sometimes unbelievible. I commute every day from Croydon to Central London on Southern or FCC trains and for the most time people are travelling on thier own as they have left the comfort of family and friends at home and haven't got into work yet to continue chat with collegues. The coaches are usually quiet with only the sound of the train on the tracks, the odd mobile phone tone and leakage from people's earphones intruding on your thoughts. Sometimes however there are groups of friends or collegues or just people who know each other and they act like no one else can hear them. This week I have over heard the ins and outs of some people's relationships - which was really (in my view scandalous) - people with new babies going out and getting off with married people (!) and I've discovered that some people are just stupid. "is that west ham or chelsea?" as we passed Millwall's stadium.
It's fun for me to listen but I bet they don't realise that they can be overheard and that people (ie me!) are actually listening