What's the deal?

OK, today it's a two-post day.
I just came back from running an errand, and once again was faced with the curse of the absent turn signal. That's right, the condition that overtakes 90% of the people in this town when they're about to make a left (or right, although that's less bothersome) turn. The offender approaches the intersection, the light is red, and they sit quietly in their lane UNTIL the light changes, when that turn signal finally comes on. It's as if they're not quite sure which way they're going until that light turns to green, and then I guess they take it as a "green light" to finally make up their minds!
This wouldn't bother me except for the fact that if there is a right lane I can enter, I'm not inconvenienced at all by the left-turning car ahead of me. If I don't see a signal, I can't know if the car in front of me is turning, and I can't make an educated decision about which lane to choose.
Maybe this is picky, but it's one of those really annoying things that I'd not encountered on such a massive scale until we moved here. An acquaintance of mine is a driver's ed instructor, and I mentioned this to him one day, and he said, "Well, I try, but it's the parents and their driving habits that the kids copy."
So there. As parents, can't we lead by example on this one?
It's the same on the interstate. As I remember from my own driver's ed (which was a looooong time ago), it is imperative to use the turn signal when changing lanes. It takes no effort, and it's helpful and courteous to the drivers around you to use a signal when you're making a lane shift. But nooooooo, that's too much trouble.
Just like it's apparently too much trouble to roll your shopping cart back to the cart corral, but that's another post......
My point is this. The world has enough problems as it is without us being discourteous and charmless to our fellow humans. Saying "please" and "thank you," using turn signals, smiling at strangers--simple things that go a long way toward putting your fellow humans in a decent frame of mind. Just think if we all worked on being more pleasant and charming. Small thing? Perhaps, but I'm not so sure...