Yes, DH and I both say 'thank you' and also LOOK at the person with a smile. Around here sometimes it's hard to get in or out of a place for people holding the doors for each other! :lol:
If you stop to think about it, it's not a good idea to answer poor manners with sarcasm, such as the loud "Thank you!" or "You're Welcome!" for more than one reason--first, we don't know if the offending party is preoccupied, stressed, worried, or just ignorant. Should we judge? Second, sarcasm doesn't teach anything but resentment; will it teach manners? Not at all. The final reason to omit the sarcastic remark is basic manners. Yes, one of the most basic rules of good manners is to take no notice of the poor manners of others. Teaching/correcting of adults, teens should be in private.