I was trained to say 'please,' 'thank you,' and 'you're welcome,' but my observation on whether these words are used can be attributed to my moving to the Scandinavian part of the world, thereby bringing me into spots in which such words are needed to have vanished forthwith. This was followed by my being whacked in the head by MS, so I'm in fewer and fewer situations in which they're used. Oh, of course there are words to be used as some sort of social lubrication, and they vary by context, it seems.