A 4 year old doesn't understand courtesy for the sake of it. I'll deal with that when I get there, and hopefully by then I'll still be able to counteract the dozens of little shits they're surrounded by every day whose parents didn't bother.
They're old people. They're just like us except wrinklier and smellier, and have a greater penchant towards buffets. All the douchebags and assholes become crochety old dustbags, and the bitches become smaller, meaner, greyer bitches. That is, until they become really old. Then they develop really old complex. If you kept talking about the same 30 years of your life and people ignoring you for 20 you would probably develop it as well. But by that time, you'd be old.