Have you ever seen a scientific experiment with things growing in a Petri dish? This is a metaphor for how neighborhoods grow as well. Things in a Petri dish grow towards the areas that have more nutrition to attract them and repel from areas that have bad things that they do not want.
It's often harder to make friends as an adult than it is when you're a child. It's even more challenging to make adult friends when you move into a new neighborhood. You may feel like people already have their own group of friends and aren't looking to include newcomers. Of course, that's just an illusion.