Most people who live in NYC weren't born or raised there. I could see why conversation would appear to be easy for them (you?). I can tell you though, real New Yorkers don't like talking to strangers.
Are you from New York? Reason I ask is because I am and even born-and-raised New Yorkers don't mind talking to strangers (or are you just talking about parts of Brooklyn?).
I'm from Brooklyn and based my comment on that. Could be that you Manhattan natives are different, quite honestly I haven't met too many people that were born and raised in Manhattan.
In my experience New Yorkers hate to make idle chat unless they've been given a reason. In general, we're happy to give directions, and we are happy to talk to people if we're in some constrained situation, like standing on line together, commiserating over transportation, that sort of thing. But if we're on the street or in the park and you approach us to talk, odds are good you're homeless, crazy, grifting, or you want us to sign some god-damned petition.
I'm a WASP land surveyor in the Mid-Atlantic region and recently I had to do an out-of-town job in Providence, RI. Our crew stayed in a not-that-busy hotel but the only people other than the staff who would talk to us were an Orthodox Jewish couple who were from Brooklyn. Maybe they just recognised a fellow traveller, but they were quite friendly and conversational on the elevator and in the common areas. People from RI wouldn't talk to us, though.
