Even though I now live in San Francisco (have been here for 12 years), I'm a New Yawyer at heart. I love New York ... I generally typify New York ... I complain about not finding good pizza ... I walk faster than everyone in California ... and I search out people who tell it like it is.
NYC and SF have a lot of commonalities (it is very common for San Franciscans to have spent time in NYC), but they also have a lot of differences.
SF: IT IS MORE PROFITABLE TO BE ETHICAL
San Francisco is massively smaller than New York -- even when you include Silicon Valley. At least in the technology arena, it seems like everyone is only two degrees removed from one another. Everyone can check up on everyone else.
Because of sheer size issues, it is much more profitable to be ethical in San Francisco (as opposed to the largely anonymous New York). People can easily check up on you in San Francisco -- so business dealings are smoother, people behave better, and everyone who is rational is extremely concerned with their reputation.
In my twelve years here, I have only known one SF guy who cheated on his significant other. Only one. (for some reason, I have known five SF women that were not true to their spouses). This is probably because the town is so small, one would likely get caught. Hence it is more profitable to be ethical.
In New York, by contrast, cheating on girlfriends and wives, while not commonplace and still unacceptable, is much more common.
And whether it is one's sex life, or their business transactions, one can screw over a lot more people in New York before one's reputation globally suffers.
BOXING YOU
San Francisco and Silicon Valley are more of a meritocracy than any place I have ever been. Discrimination in SF is based more on one's brain than on one's background. In all my dealings in the Bay Area, I have never been asked, in a business setting, what my father does for a living or what high school I went to. Those are very East Coast questions.
In New York, people are always trying to put a box around you. Where did you grow up? What church do you go to? what is your ethnicity? What club did you join? How many middle names do you have? Not necessarily to discriminate (as I find New Yorkers extraordinarily friendly and inviting), but more to try to better categorize someone. In New York, it is far more important that one is Jewish and went to Exeter Academy then that information would be in San Francisco.
OPENESS
A New York friend is far more likely to invite you into his home than a San Francisco friend. I have no idea why, but New Yorkers are some of the friendliest people I have ever met. Need a place to stay? Want a meal? Need help moving to a new place? Look no further ...
San Franciscans, by contrast, are connectors. They might not let you stay the night at their house, but they are happy to introduce you to Tom Siebel or Jerry Yang in a business setting. No one in New York has ever offered to introduce me to Hank Paulson or Stephen Schwarzman.
TRANSITORY
My guess is that after Washington DC, San Francisco is the most transitory city in America (maybe tied with Atlanta and Phoenix). It is hard to find someone in SF that is actually from SF. Many people are immigrants or transplants (including thousands from New York).
NY has is share of transplants, but much of the nightlife and business-life revolves around people that have been in the New York area for generations. Old money is more important. In New York, your high school friends are more important ... in Boston, your college friends are more important ... in San Francisco, your business school friends are more important ...
Because SF is so transitory, people are far more open to meeting new people.
RELIGION
Religion tends to be deemed more important in New York. San Francisco has one of the highest rates of intermarriage between religions of all American cities (that is probably due to the fact that SF also has lowest rate of people who regularly attend religious services).
Though New York is certainly not the bastion of religious zeal, it does promote more adherence to God. That might be because tradition is much more ingrained in NY society (and there is a historic church or synagogue on every corner).
SMALL CITIES CHANGE BEVIOR
That's right, small cities like San Francisco (where everyone is maximum of two degrees from everyone else) massively change behavior.
First, people are more social ... what? You say people are more social than in New York?
Definitely.
My guess is that the average San Franciscan has double the amount of acquaintances than the average New Yorker. Double.
They probably have the same number of "friends" -- but twice as many people they know and like (the next step beyond friends). eVite originated in SF because of the dotcom craze -- but it also originated here because there more of a reason for evites. Parties of 50 people that all know each other are commonplace in SF -- they're rare in NY.
This is, of course, due to SF's size and transitory nature. When I go out in NYC, I go to a bar with three friends and maybe, just maybe, we happen to run into someone we know there. In SF I go to a bar with three friends -- but I already know that they'll be at least 20 acquaintances there. Now all these acquaintances brought their friends -- so what happens is that I go into the bar knowing 20 and I leave knowing 30.
And clubs ... how many people in SF do you know that joined a social club? I think I might know three. But many of the people I know in New York are part of some club -- whether it is the Harvard Club, the Metropolitan Club, the banana-split with all the toppings club ...
Why the difference?
Because New York is about those boxes ... SF is about off with the suit and tie ...