I have visited NYC a number of times as a tourist, so my opinions are not reflective of someone who lives there. NYC is an incredible place, full of both interesting and odd people, wealth and poverty, crime, artistic inspiration, exotic foods and cultures, and a melting pot of ethnic people.
I would imagine the politics of ruling over that kind of chaotic environment could be frustrating for police officers if they are not supported by their government. I would love to visit there often, but could not see myself living there.