Lived in NYC for a bit, and while normally large groups of people put me off, the city was absolutely amazing in a sense that I felt tiny. Everybody going about their own business and such.
However, when it comes to adapting and immersing into new social groups and communities (i.e. school, work, duty to interact, etc), the transition is normally very rocky and unpleasant until I feel comfortable around those I share frequented, common space with.