I think when we first moved in, I was somewhat influenced by the book Katt read about how you need to try hard to make friends by talking to lots of people. So, I made sure to say hi to the next-door neighbors and had small chats. Also, I bumped one of their cars with our rental truck so I felt really bad about that.
Over time, I unconsciously reverted back to my state of nature. When I open our side door, and I make eye contact with my neighbor, I do say hi, but then try to quickly move on because I really do not want to chat every time I open the door to toss out compost.
But the same applies when I go out the front door. I do that because I am trying to go somewhere. I also do not want to chat then. If not then, when though?
This is what's hard about the whole "everyone should talk to people who are different from them, and then there would be less polarization" idea. It's way easier to talk to people you have something in common with! My neighbor's not a Trump guy or anything like that, but he is an older Brazilian man with a blue collar job, so weather, people's gardens looking nice, and home improvement are basically the entire conversation topic list.
I guess at least I can continue to say hi, which is not building bridges but isn't burning any, either.