Hold that door, please.

Since when do men not open doors for women?
Is this because so many women have demanded independence, and men are confusing common courtesy with women asserting themselves?
I can't tell you HOW many times I've been literally steps behind a man walking into or out of a store and had a door slammed in my face. Are they so unaware of their surroundings that they don't know I am behind them, more often than not carrying a 20 pound child in my arms? Were they not taught by their Mothers (or scolded by their wives) that it is proper to hold the door open for a woman carrying a child? Do they just not have manners? Are they confused about etiquette? Or, do they just not care?
My 11-year-old knows better than this. He uses words like "please", "thank you", "sir" and "ma'am". He holds doors open for elderly people, women holding babies and younger children. My heart swells with pride every time I see him do this. I know I have taught him common courtesy.
The funny thing is that often when I do something nice for someone (ie pick something up that someone dropped and hand it back to them, hold a door open for someone else, move my cart so someone can pass around me in the grocery store), no one seems to say "thank you" anymore, either. It's like having manners has become a lost art. People seem to expect courtesy themselves, but often not offer it in return.
What happened to manners? Where have they gone?