I get treated as a foreigner in Edinburgh to this day because of my accent. The UK have given me very different receptions over the years, so here's the results so far...

Stockholm: 10/10 - Random student having some post-graduation party decided she would be our tour guide for an hour or two and just took us around on trams and whatnot, showing us cool places and teaching us words, it was great. Everyone was friendly.
Newcastle: 10/10 - Just such a lovely accent to listen to, and generally lovely to all people. Happy to talk to strangers about anything and not judgemental.
York: 9/10 - Basically really friendly and great people in general, who treat you sort of like you're already friends/family.
California: 8/10 - Very friendly people but some of them were not interested in being helpful to you at all. A train driver, for example, told me I had to board at a distant carriage, then just as I started moving down he hopped into the train and it took off about five seconds later.
Menorca: 7/10 - On occasion someone would not be interested in speaking to me because I didn't speak Spanish, but that was only once or twice in about a week, so it's not too bad.
Edinburgh: 6/10 - Not bad. Treat you like they don't care if you're a tourist or not a tourist, if that makes sense. Not rudely, but just... like customer service on a telephone, I suppose. It really depends on where you go, though.
Wales (except Cardiff): 6/10 - A bit like Edinburgh.
Germany: 6/10 - Hard to judge considering I rarely spoke to anyone who spoke English, as I was in a small town. Nice enough, I guess. Polite. Some made an effort, some were not interested at all.
London: 5/10 - Just not interested.
Glasgow: 5/10 - Some are lovely, some are most certainly not.
Ireland (Outside Dublin): 4/10 - Nicer than inside Dublin, but they still make you feel more like a "foreigner" than a "visitor".
Cardiff: 3/10 - Dublin and Cardiff seem to have a little bit in common (see below). My time in Cardiff was very short, though, so maybe it was just bad timing.
Ireland (Dublin): 2/10 - Grumpy moaning Dubliners, I tell ya...