Ps and Qs

It seems like I've always known that minding my Ps and Qs means to act graciously.  However, this is a common term that I only explored recently.  Whether we attribute the origin to "pints and quarts" or to the typeset letters, we are reminded to watch what we are doing.  I was intrigued to learn that one possible origin was an English bartender's charge to watch how many pints and quarts a customer might consume.  Another possibility is the attention to detail required to discern the difference in the letters "p" and "q" in proofreading typeset material.

I'd like to offer another possibility - Presentation and Questions.  Continuing the theme of acting graciously, consider all elements of presenting ourselves.  Are we prepared, professional, prompt, presentable, positive, precise?  As for questions - are we prepared and willing to address them, and eager to solicit additional queries?  Our ability to present information and address questions in settings large and intimate ultimately determines how others judge our mastery of Ps and Qs.