In the suburbs, neighbors are often (not always!) super friendly. My neighbors and I have watched each others' pets and helped each other in a lot of ways.

I think it's just the "buying" versus "renting" thing. In the city most people are renting. There's less incentive to make friends with your neighbors when in the medium-term future one or both of you will probably be somewhere else. Your rented property is truly often just a place to keep your stuff. I think rental neighbors should still try to be friends for a variety of reasons (why wouldn't you want to get along with and help your neighbors?) but this is a minority opinion.

On the other hand, when you and your neighbors are all in the midst of 30-year mortgages, people often put more effort into getting along and forging bonds. More of a "we're all in this together, let's try to get along" thing. One of our next-door neighbors is actually kind of unfriendly.