[CaptainDecisive]

I lived on 2nd Ave NYC for a while which matched your observations on interacting with neighbours. However there's an interesting urbanist video [1] that suggests that even in a higher density neighbourhood with appartment buildings, the amount of traffic on the road affects both how many friends you have and how much you socialise with neighbours in your building. Ie in a car lite environment, everyone is friendlier.

[1] https://www.youtube.com/watch?v=ESgkcFbGiL8