Here are some... I couldn't resist.
Calling NYC the big apple.
Only people from the suburbs and outer-boroughs call Manhattan The City.
Telling a New Yorker how big and cheap your apartment in Kansas is... You're not in Kansas anymore.
Asking a celebrity that you see on the street for their autograph or picture.
Ordering Ham and mayo on white bread at a Jewish Deli.
Pronouncing Houston Street as if it were a city in Texas.
Telling your life story when asking for directions
Making eye contact on the subway
Not letting people off the subway train before entering
Not cleaning up after your dog
Calling Sixth Avenue "Avenue of the Americas"
Calling the former World Trade Center, "Twin Towers"
Driving a car in Manhattan with NJ plates
Not giving the Taxi driver directions
Raving about Rudy Giuliani
Arrive early for a party or never know when to leave
Jumping in front of someone waiting for a cab and get in
Not walking fast-enough