I haven't lived in manhattan ever, but I used to spend weeks there in 2014 for work (also in DC), and I've lived in London for a few months and now SF for years.
Cities generally have more variety of types of food (Burmese, Indian, Thai, Chinese, Italian, Jewish, etc.) that can be hard to find in the midwest (I grew up in the rural-ish suburbs outside of Buffalo - maybe not technically midwest, but close enough).
You have a lot of things close to you, you can walk out of your apartment and have a ton of options right here, in NYC you can subway anywhere else easily. The density makes things feel more like a community vs. houses spread apart where everything is by cars and strip malls.
In NYC you can go to the comedy cellar on macdougal street one night and Chris Rock or Louie CK might drop in unannounced to practice material (happened to me twice and I didn't go that many times).
If you live in a major city lots of friends pass through for one reason or another and you can meet up with them (this literally never happened in the suburbs of Buffalo).
There are also often more events and variety of people which can make things more interesting. It's also a lot different visiting vs. having your own place there for an extended time. Visiting is often more stressful because you don't have an easy place to retreat to.