In the US though, people can get very aggressive even if you accidentally brush against them. Today some Londoner, huge guy, practically punched me in the arm as he slipped by me. Plenty of room on the pavement btw... Back in NYC, I've seen fist fights break out because someone touched another person on the pavement. If that guy happened to pop into the US, and if he *punched* someone like that on the street...
This is true. It's the same with inconsiderate behaviour in general. In the US if, for example, someone were to pile their stuff on top of someone else's at a checkout counter, there would be a very loud verbal exchange. Whereas, in the UK, there would just be some eyerolling and muttering under the breath. Which is why, I think, that there is more of this type of rude behaviour in the UK - there's less of a risk of being involved in an altercation because of it.
I've never been aware of any particular etiquette for passing in the street. It's just one of those things where you make an ad hoc decision which way to move based upon which side of the center line of the footpath you each happen to be, which way the other person looks as though he might be going, etc.
The difference is, in the US, you don't wait until the person is ready to pass you before you decide which way to move. As soon as you notice that someone is eventually going to pass you, you automatically move to one side or the other, and they do the same, even if they are all the way at the other end of the street, so that by the time you actually pass each other you are already out of each other's way and don't have to think about which way to move. Similar if someone is walking behind you - you automatically move to one side in case they want to pass you. And if you are walking side by side with someone and someone is behind you, you and the person you are with change to walking single file so the person behind you can get past.
Another thing that I found shocking is the drinking culture in the UK - I don't mean binge drinking, but the way so many British people seem to be incapable of socialising in any way unless they are drinking alcohol.