This is kind-of an oddball question but the site rules don't appear to forbid it. If it somehow violates guidelines just let me know and I'll voluntarily take it down.
I'm looking for region-specific curses, ones that can easily pin down the speaker's home territory, in this case New York (the city and surrounding metro area). For example, in much of the "Bible Belt" areas like Kentucky, one of the most well-known examples of a regional curse is "Bless your heart!" It sounds innocuous to an outsider, but coming from a local that is about as harsh as you'll get.
So what's a good equivalent in the NYC area? Something that would easily identify the speaker as a "New Yorker".