Catherine, a few more comments about politeness of Americans. As I said in my original response, some Americans, partigularly those who came from homes or schools where politeness was taught are polite. Someone mentioned that he grew up in the South where politeness was taught and used everyday and I know that to be true having lived in the south. However there are other reasons why people are polite. Waiters and waitresses are polite because their tip dépends on pleasing you. Some of them get nothing as pay except the tips so when you don't tip very well or not at all due to preceived bad service, don't expect them to be so polite when talking about you to their colleagues. I always tip very well because I know how little them make even on a good day. Sales people are polite because they want to sell you something. However, they recognize they won't be able to sell everyone so it doesn't change their attitude when they don't succeed. Customer service people are trained to be polite on the telephone and they are monitored to make sure they are. However, you can't blame them when they think bad things if they encounter boorish callers who are obnoxious. Good manners are learned early in life and they become Embedded in the persons daily interactions with people. Americans who come to France are fish out of water in terms of language. They are dependant on others understanding their broken French, to give them instructions to resolve the bureaucratic issues, to find the services they need, etc. They have to be polite to survive. I knew one Canadian couple where the husband worked in the UN and the wife stayed home and after many years, she never bothered to learn French but complained constantly about France and the French. I really found her to be irritating because she caused her own problems by never Learning French.
Too often, now in American families and schools, manners are not taught or reinforced daily so that they become habit with the kids. As I said, some Americans are polite and some are rude. Unfortunately it seems the "animals" are taking over the zoo on the internet.
Thank you for your compliment. I'm glad you ran into the well mannered Americans. However, if you travel in the US you will meet the uneducated types. I'm sure this is true in every country. I've had rude and good expériences in Germany and England as well so there is nothing particular about America. It's a worldwide issue.