I don't think any other city in the world... the sun doesn't shine the same way anywhere as it does in New York. And then I guess everyone's very good at hanging out. Not in a crazy way, but you're just constantly interacting and learning.
I guess something that I've noticed from American acts who had success in touring is more of an explanation as to their music. Which is I think quite funny. I think British acts might like to leave more to the imagination - maybe a bit more obscure perhaps - a bit more shy.