Just the opposite of what our Moms told us.
I found an article online at The Atlantic about the benefits of knowing your neighbors. Social connection at the neighborhood level has long been known to be associated with good mental health, and some aspects of physical health. But this is the first study to look specifically at neighborhood social cohesion and heart attacks, which hit more than 700,000 Americans every year and cost everyone billions of dollars.
In my experience, it benefits me to know my neighbors. If I have a problem or an issue with something they have done, it is easier to start a conversation rather than have a confrontation. I would let everyone know if we were entertaining so they would be forewarned about lots of cars. Mr. Ralph taught me to use the "sandwich" approach when delivering bad news. Say something nice, bring up the issue, and end with something nice.
Also, some day you just might need a favor. If you have a friendly relationship with someone, it's easier to call and ask for help. Borrow an egg or a cup of flour? Have a special kitchen item to lend so I don't have to buy it to use just once?
No need to be best friends with everyone. If you don't want to. But friendly neighbors are important ... emotionally and now physically!