“The blab of the pave … the … talk of the promenaders”
— Walt Whitman, “Song of Myself” (cataloguing the delights of the City)
I continuously see people on the street, in the park on sidewalk benches, in gathering places such as cafes and bars — everywhere — in pairs or larger groupings, engaged in deep conversation and repartee.
People feel less self-conscious in New York. Free to express themselves. New York encourages thought and exchange of ideas.
Addendum: Another thought. The fact that NYC is in large part a city in which people are on foot when they are outdoors, and not in cars, but instead are walking, or resting on benches, say; and, when they are traveling, are often on subways or buses, where conversation frequently occurs, is a facilitator of conversation and interaction.