I pretty much agree with you, it seems like things have got worse - actually London seems to be particularly bad, far worse than up in Scotland. I'm the same as you, I try to be polite and courteous: a couple weeks ago I gave up my seat for a pregnant woman on the crowded tube and she wouldn't stop thanking me, which makes me wonder whether it was the first time someone had done that for her. I often get doors swung back into my face because the person in front couldn't spare an extra second, or shouted at because someone decided to walk into me. After being in Japan and on their public transport, it makes things seem so much worse.