P's & Q's or p's & q's

The other day, I was driving Miss Lucille to town.  I happened to mention that I was going to look up the saying for "mind your p's and q's."  I had always thought it had something to do with etiquette.  And I mentioned this, as I often mention mundane or not so mundane topics for my journeys among the great library of the 'net as I like listening to her take on life.

Upon giving me the ol' eyeball, she proceeded with this:  In the old days of typesetting newspapers,  the p and the q (p q) looked so similar, that you had to be careful and make sure the right letter was used. One was frontwards and one was backwards.

Here, all this time, my mind insisted that p's and q's had something to do with etiquette.  Though, now that I think about it, my father, a former news editor, also told me this.  Why do some children never pay attention to their parents on a lot of topics?  If I had, it would have spared me the eyeball from Miss Lucille.

Hmmm.  Could it be the fact that one of my teachers in high school liked to say that all the time?  She used the expression whenever we were a mite restless.  Though, now that I think about, she did so whenever we weren't paying attention.

The question is how did I get etiquette stuck in my head?

One little saying, two different interpretations, a lasting impression.  Hmmm.  Many things to keep in mind when I write my many words.  I wonder how long it will take for me to get the correct interpretation to stick in my head.  Next time I ask, there might not be anyone who could readily tell me this from the rich and varied experience of their life.  I might have to search for hours, if not days, in the great library of the 'net.