I don’t like NY very much. Sorry I have a different opinion here.
It is too noisy and crowded for me. As for shopping, it is true that all fashion brands have their flagship stores in the City, but they are spread over different locations and the environment is not good either. For example, Shorthills and King of Prussian are huge and nice, and I think they both are better than the department stores I have visited in NY city.
However, however, it is definitely the best “People watching” place in the world. You can always find men and women dressing so fashion. Maybe people have to learn to be sophisticated to survive in the City :)