Me too - very important! DS1 has been reminded for aeons - he is very nearly 3. They are finally starting to come out spontaneously some of the time - and he certainly knows when they should be used, as a raised eyebrow is all it takes to remind him. I am confident he'll get there, and it will be a Good Thing.
Cannot abide lack of manners - get apoplectic in my car when drivers I have let through on a narrow bit (lots of those where I live) can't even lift a finger to say thank you, and have been known to roll down the window and bellow at them