In fact, a friend who recently returned from there said people in the British Isles aren't "friendly" at all, in the American sense. No "thank you" "please" etc.. If you attempt it on them, he said, you're regarded as a Martian might be...
You have to make a distinction between "manners," much cultivated (if I may indulge in a stereotype) in Europe, and "friendliness," which is what we believe in here in the good ol' USA.
You can be very friendly and still be rude as hell. In fact, you're almost bound to be. I remember being in a grocery store in Washington state, and the checker was, in a perfectly cheerful way, asking all kinds of (what I considered) very intrusive questions. "Where are you from? ... What do you do for a living? ..." I got out of there before she got to "How much do you make?".
This would all be considered highly improper anywhere in Europe.
It's also possible to be extra-polite and unkind at the same time. In fact there's a particular style of perfectly correct politeness that's specially designed to make the other person feel like shit. I even know some people here in the US who practice it.
But from what I've gathered from the alt.usage.english newsgroup over the years, British people don't necessarily indulge in all the inane chitchat that Americans do.
Typical "conversation" in an American store:
Clerk (handing you the receipt): Thank you!
Customer: Thank
you!
Clerk: You're welcome! You have a nice day now!
Customer: Thank you, you too!
Clerk: Bye now!
(This is after buying some paper towels and a candy bar).
An exchange like that would be impossible in England, from what I understand. Any actual Brits care to weigh in on this?