Why do New Yorkers seem rude?

From Smithsonian Magazine's May 2008 issue:

In my experience, many people believe that New Yorkers are smarter than other Americans, and this may actually be true. The majority of people who live in New York City were not born here. Indeed, more than a third were not born in the United States. New Yorkers, then, are people who left another place and came here, looking for something, which suggests that the population is preselected for higher energy and ambition.
Also for a willingness to forgo basic comforts. I grew up in California, where even middle-income people have a patio on which they can eat breakfast and where almost everyone has a car. In New York, only upper-income people enjoy those amenities. The others would like to share them. I sometimes get into conversations with taxi drivers, and since most of them are new to the city, I often ask them what they miss about the place they came from. Almost always, they name very ordinary pleasures: a slower pace of life, a café where they could sit around and talk to friends, a street where they could play kickball without getting run over. Those who miss these things enough will go back home. That means that the rest of us, statistically, are more high-strung, hungry and intent on long-term gains—traits that quite possibly correlate with intelligence.

This might just seem interesting to me since I live in New York and we're always looking for justification in paying more for our small apartments and groceries. In any case, read the rest of the article here at the Smithsonian Magazine website, or check out this month's issue.