No matter how much you hate cars, and I really hate them, carrying everything you might need in a day -- gym clothes, sneakers, lunch, files, book to read -- on your back or shoulder can make you feel like a pack mule after a while. A grumpy pack mule with a persistent ache.
No matter how much you are creeped out by an America that aspires to nothing higher than positive consumer experiences, gleaming floors, wide aisles and bright lights, you will get sick of buying your food in places where the floor is dirty, it smells weird, they have no squash you can recognize but are well stocked in these thingys that look like anteater snouts, and the brands and flavors of yogurt they carry vary by the day.
No matter how much of a "foodie" you thought you were, making tea with what looks like an old-fashioned shaving brush, coffee with a set of glass tubes and cocktails in barrels for aging is bullshit. And putting bacon in everything is really not that cute or clever after a while.
No matter how good of a sense of humor you have about things that are both gross and inevitable, you don't want the first thing you see when you emerge from underground to be someone's vomit frozen to the metal stairs.
Not everyone has these experiences, of course, particularly not the first. But if you come to New York neither wealthy nor idle, be prepared for a pretty serious grind. It conjures visions of the capital city of an on-the-rise third world country, a glittering playpen for the fortunate ringed by layers of crowded and dirty shantytowns for everyone else, complete with benevolent billionaire overlord. At least we have really excellent drinking water, I suppose.