I've come to the conclusion that I dress my best when I'm in NYC (still is so surreal to say "when I'm in NYC as if I am here on vacation, which I am!) And I honestly don't know the exact reason why this happens to me and my wardrobe (?). I wouldn't say is the pressure of looking your best there because in the US you have freedom of speech and that comes with a freedom on how to dress, but I think there's like a thought in the back of my head that I really need to step up my clothing game while I am there. Also a great way to just add that little something, is great shoes! and lately I've been buying too many boots!
I also think that it happens because we all have heard so many stories about New York and we, society, believe so many different things when it comes to the capital of the world without even realizing we can change those thoughts. Like, I saw a picture yesterday where it said " Welcome to New York, your feelings mean nothing to anyone" and it is so true but at the same time such a lie! If we all believe that it will be that way, if we don't we are just going to create a beautiful world. 
So maybe that's why I dress my best, maybe yes, may be not. But I am 100% sure that I love to dress  and how I dress in NYC!