Common Courtesy

I don't know if it's a regional thing or an age thing; but, it seems that common courtesy is fading fast in this country.

When I lived in Virginia, people would say hi when walking by each other on the street. I've gotten into the habit of saying, "How ya doing?" I guess this is a bit much. I really don't expect an answer; but, if they did, I would listen.
I've also started to say excuse me when I get into someone's personal space, I define that as being within arms reach.

Now living on the west coast, I've noticed that people tend to avoid eye contact when passing each other. But, I've noticed that older people will greet. Maybe it's a generational thing.

I also like to open doors for people. I heard that this is insulting to some people???? Wow. Well, how about not letting the door slam in the face of the person behind you? Is that respectful enough?

I think I'm the only one who will leave the room to answer my cell phone. Actually, I should silence it when I'm eating, in a meeting, or just conversing with an acquaintance.

We don't need to go over "please", "thank you", and "May I"