The two times I have visited NYC I have found the locals friendly. Then again I bring out the best in people.
I've met friendly people there too. Used to go down to Manhattan about every three weeks when I lived in Connecticut. Most of the friendly people I met in Connecticut were from other parts of the country. Or black. White locals were either SOB's or were trying to scam you. Or in a couple of cases were good guys explaining how tough you have to be to get by in area. Most places I've lived had one garbage company, or the city itself, collecting garbage. In Greenwich neighborhood had about 30 different collectors, all Mafia connected. Complain about service and they may not collect again for a month or more.