Only the cities?

Humans are social creatures, even the introverted ones. They, we, need company, possibly like-minded people. Something weird is going on when you have 600 friends on Facebook. The optimal size of a community is about 100-150 people. This is the size of a community where you can say, everybody is your friend - or enemy. This is the size which allows you to know well each other. Look for this size.