New Yorkers, especially those who have been there for at least 10 years, the length of time Ed Koch says it takes to be a real New Yorker …
From the awesome post on Gawker: I Used to Love Her, But I Had to Flee Her: On Leaving New York
Best thing I’ve read about what it’s like to live in NY and try to make it, why it’s so hard to leave or fathom living anywhere else, and then what it feels like to have left (I lived in NY for nearly 13 years before moving to the Bay Area).
Raanan Bar-Cohen 
My answer is: less time than it takes the typical SF pedestrian to cross the street. People walk really slow here. One of the big adjustments from coming from the east coast (esp NYC)..
Ha ! Very true …I still walk at a crisp NY pace …