I mostly scoff at the American regional stereotypes, that New Yorkers are assholes and New Englanders are brusque, Californians are laid back and the Midwest and South are so friendly; I've spent time over a lot of the US and I've almost never seen it.
I see it a bit in winter, though. Milwaukee waxes gregarious in the winter: even on the tiny side streets people lean over railings, clinking bottles of beer, congenial laughter in the face of the cold; late at night we pass each other on the street and we exchange small smiles, shared bemusement at our own survival, hissing into our scarves.
In Boston we were affable in the light of the train, watching the skyline or the freezing Charles, but late at night the city grew stark and ethereal. The snow crunched under my own feet, and yellow light shone from sad buildings, but we wrapped the silence around ourselves. I tilted my head and the cold crept under my scarf, tracing my collarbones. I liked the way the wind wound through the old roads, picking up smells: the tendrils from the ocean, the clarity of the ice, the way the firewood dilutes the scent of decay.