Here are a few thoughts on this subject written by an English girlfriend of mine who moved to New York.

Americans are so fierce! I even have conversations with randoms on the ‘subway’, can you believe it? As barking mad as it sounds, it’s actually rather lovely. I mean, God, if a stranger spoke to me on the tube in London, I'd presume (correctly) that they were a crazy crackhead, and I'd get out at the next stop, whether it was my intended destination or not. Here in New York, I've had strangers on the subway asking me what book I'm reading, and I'd show them the cover (I'm not quite ready to fully speak back to them), then someone else would say that they've heard that it's a great book, and then a mini-subway-train-book-club would form. All rather embarrassing, but still, quite endearing at the same time. When I get over being British, I’ll fit right in! (Although, having a conversation with a stranger whilst sober is still a little much though, wouldn’t you agree?)