My mom was born in Erie and grew up in NYC in the thirties and
forties. She absolutely loved the place, apparently being a theater
and concert-goer as well as quite the party animal. She also worked
for a Mafia-run business and said she never had a better boss.
Anyway, I would consider her an authority when she says that there
is no rudeness like New York City rudeness. It features a certain
brusqueness; a lack of concern for anyone but oneself, an attitude
of "get out of my way, I'm doing something important".
Now, obviously this is a kind of survival mechanism bred into the
populace (and accepted as the norm) to help cope with the very real
stress and danger of living in one of the noisiest, most crowded,
filthy, and dangerous places in the world, or perhaps the galaxy. It
was obviously collectively decided a long time ago that it was
hopeless to try to hold one's neighbors to even the tiniest
standards of civility. Note that this is the usual human reaction to
overcrowding, and far from unique to NYC; falling back on
hyperpoliteness, like the Japanese do, is not the usual defense.
In the Vegas mode (nice segue, huh?), the last time I visited New
York, New York, I thought it would be far more authentic if the
change people dressed in rags and tried to get change FROM you, and
if you asked, say, a security guard: which way to the coffee shop,
he'd grab his crotch and sneer, "I got your coffee shop right here,
pal!"