I just say hi and then maybe talk about their dog, my dog, or something else surface level.(“How about those ‘Sports Team Name’?”, “You see that awesome new movie/show?”, “Hey, did you hear about ‘Local Event’?”). I stop to chitchat when I have time and I usually get to know my neighbors. We keep an eye on each others places/cars/etc., have taken care of their dogs while out of town and vice-versa and one of them is an emergency contact for my kids. Its way better to make friends than just be living close to a bunch of strangers. Not everyone is super social, but I still know pretty much all their names and they know me.