I currently live in Denver and spend almost every weekend in the mountains. To me, the depressing part of NYC is the complete lack of fresh air, outdoor activities, and solitude.
Different strokes for different people.
Different strokes for different people.
The most well known maybe, but not the largest. Pelham Bay Park in the Bronx is more than 3x the size of Central Park
You can see quite a bit more like the Adirondacks you're willing to drive 5-6 hours, but a drive like that isn't suitable for a day hike.
You can also find some smaller trails and untended areas on the outskirts of the city (eg, Marine Park in southeast Brooklyn). But these tend to be.. well small.
Anyway my point is, like most big cities, it's difficult to really get "outdoors" with any measure of convenience.