It's a familiar cliché: the big city breeds a general lack of consideration for others and promotes rudeness. It really should be true, but in my experience it simply isn't. In Edinburgh, London and Manchester we've met with unfailing politeness. Of course, the crowds continue to hurry by, but doors are held open, people stand to one side to let others pass, they apologise when there's an accidental collision, and it's 'please' and 'thank you' all the way. I can't think of a single time we've been served in a shop with any degree of abruptness.
Yes, the world is in many sad ways horrible, but it's intriguingly a nicer place than you think.