The pedestrians are very aggressive. Example: Rather than wait for the walk signal they walk when when the lights are red for the cars. What if cars run the red light?
Example: Sometimes when there is a lull (and not absence of cars) because cars are turning away instead of coming straight, pedestrians surge into the street taking up half the road. They sometimes stare down drivers who are forced to stop even though they have the green light and they have occupied the street.
Traffic in Washington DC in comparison seems extremely sedate. Note to self when in DC: Take a deep breath and think, New York, New York.
Not related to NYC, but perhaps the culture that is NY? Last summer in update NY we stopped for lunch at an Italian restaurant. Near the end of the meal the waiter asked if I would be paying by cash or credit card. When I said credit he sighed and said it was too bad - if I were paying with cash he would not charge me the sales tax. (Yes, it was a rather expensive lunch.)