I think it depends on what type of public transportation you're on. On the bus ride from Derby to Nottingham, I take a coach bus (The Red Arrow) and I'm generally undisturbed. Rush hour is terrible, though, as it's always full. Yesterday there was a drunk a**hole on the bus who wouldn't shut up.
I have also experienced what you've experienced on the public buses here. The music that people crank is absolutely annoying. I honestly dislike the bus in general, as there are so many annoying people clogging up the seats, talking loudly, eating food on the bus. It truly depends on the mode of public transportation, though, as I think the trains are quite better.
I absolutely hate the mobile phone thing. On the bus ride home from Nottingham today a woman was having a full fledged argument with her boyfriend on the phone, yelling at him, repeating herself. It was just terrible. I was sitting with other passengers that found it to be equally ridiculous. By the end of the bus ride we were all laughing about it... but seriously... an argument, on your mobile, on public transportation. Ugh.