I know that sometimes we expect someone to acknowledge that we have spoken to them. The only time I feel I need to be acknowledged is if I'm in an environment that may make it hard to be understood. If you are competing with other dialog or it is noisy then I will expect at least a nod. Maybe you are
being a little over sensitive to what may be someone that is not that comfortable in social situations. I have also known people that ignore you when
you ask a direct question. There are sometimes conflicts of this kind when backgrounds are totally different, since it is sometime hard to get on the same page.

I never called my first mother-in-law 'Mom' and it was never a problem. I would not have felt comfortable calling her Mom because of the way she was. My
present mother-in-law has a nick name of Grams and that is what I call her. Before the Kids came up with Grams I called her by her first name. I
am close enough to her that I would call her Mom if you ask me to.