I think the “Good Shabbos” thing is rude, not a halachik thing. Where I grew up in Monsey, everyone said good shabbos to each other. We had a nice mix of people (though mainly MO) and everyone joined in. As the community got more and more right wing, people started ignoring others. In my opinion, sort of going against the “minhag hamakom.”
I really try not to say good shabbos to people who look like they dont want to answer me, but sometimes I “slip up” and when they dont answer, it does bother me. You dont even have to look at me, but please, do not ignore me.
Also, please do not cross to the other side of the street. I will avoid touching you. I will not reach out to grab you. I will make sure you have plenty of room not to touch me. Please dont make me feel like a leper though.