...but I impressed a friend with my parenting because I say please and thank you and so forth to Simon all the time. Even for little things. But hey, manners start early. I'm polite to people in part by nature and in part because I really do feel you get more out of life if you're nice to people. It usually makes them want to be nice to you in return.
We do the same with our three. My figuring is that if we went to a restaurant, I wouldn't say "Thank you" to the waiter just the once, I say it every time (s)he performs a service at the table. So with the children - if they do something for us we say thank you.
It has to be said it's a work in progress. Our oldest is now seven, and he and his younger brother (four) both occasionally have to be reminded to say thank you when we give them food, although the younger one usually says "Excuse me" before he starts another round of incessant talking. In public, however, their manners are pretty good - it's gratifying having teachers and other parents congratulate us on their manners.
I'm one of the group who holds a door open for anyone who's near, and who doesn't mind if a woman holds the door open for me if
I'm near.
And as for toilet seats - at home the seat goes down completely for flushing, but at work in the gents' it stays up.