For all of you that don't get a thanks when you hold a door for a woman, let me assure you there is at least one woman out there who appreciates it and you.

I make a point to pause, look the person in the face and say, very clearly and kindly, "Thank you!" And if they throw in a polite, "Ma'am," while holding the door they get a, "Thank you very much," and usually a "Sir" at the end.

Courtesy should not go unacknowledged and unthanked.