New York magazine's Ann Friedman explains why she did:
New York is increasingly a city for people who are already on top, not for those looking to establish themselves. I've always been partial to the friendly guy who doesn’t know how hot he really is (Chicago) or the surprisingly intelligent, sexy stoner (Los Angeles) as opposed to the dude who thinks he’s top of the list, king of the hill, A-number-one.
In an excerpt from Goodbye to All That adapted for BuzzFeed, Ruth Curry describes the heady infatuation with New York that I never managed to feel: “The city lent itself especially well to a mental configuration in which you were an extra in an artsy, high-budget movie and saw everything as if through a camera on a set.” Part of that infatuation is a willingness to consider New York from a cinematic distance, overlooking the city’s many irritants except insofar as they add grit and drama to your story. This seems like the general approach of many New York evangelists, who complain vigorously about little things like subway hardships and bedbug plagues, and then post Instagram photos of the skyline at sunset. A not-insignificant number of the vehement New York lovers I know — especially the young twentysomethings — are actually pretty unhappy day to day. I picture the prom king’s girlfriend sitting near him at the party, ignored but still kind of proud to be in the room and on his arm — and incredibly defensive should you suggest she break up with him for someone who dotes on her more. When I describe my West Coast existence (sunshine! avocados! etc.) to some New Yorkers, they acknowledge that they really like California, too, but could never move there because they’d get too “soft.” At first this confused me, but after hearing it a few times, I’ve come to believe that a lot of people equate comfort with complacency, calmness with laziness. If you’re happy, you’re not working hard enough. You’ve stopped striving.
For my part, I moved back to Chicago after three years because I didn't want to hate New York. It worked. I still love New York, but in the way a person can love an ex: I keep up with what she's doing, and we have coffee every so often, but that's about it.