> The culture of the city I just came from was different. People would assume you wanted something if you opened your mouth or looked at anything but the ground a few meters in front of you. For more than a decade I lived in a place where people weren't nice to you unless they were selling something.

Honestly, I've heard this a lot, but I moved from a suburby area to one of the densest cities in the country and IME, people who feel this way are people who haven't really tried saying hello. I make eye contact with strangers and say hello pretty often, and I never really get anything but smiles and friendly replies in response. The same thing applies to chatting to people when waiting in line or whatever, etc. This isn't just a bubble thing, because I live in a pretty grubby area but also socialize in a lot of swankier areas, and I've found it to be pretty universally true.

TL;DR: You get out of a community what you put into it.