What does it mean to "watch your P's and Q's"?

Question

I've heard that phrase before, but I don't really know what people are talking about... ^^;

Answer 1

be especially alert not to embarrass whoever's telling you that. lol

Answer 2

Before you ask something, you should enter in the "search for questions" box. This one is already answered. (As are about 75% of the questions people ask.)

Answer 3

This comes from sailors when waiting in port to get paid or waiting  for their next job, the taverns would allow them to run a bill. They had to watch how may Pints and Quarts (P's and Q's) that they drank, or they would owe their entire wages to the tavern. That's where it comes from.

Answer 4

It basically means to mind your manners, or give more respect to someone.  

Answer 5

To mind your manners

Answer 6

From an old printer's axiom. Back in the early days of printing presses, each line of text had to be set up one letter at a time. Since the letters in the press were reversed (so they'd print forward), the printmaker (or typographer) needed to be careful not to confuse one letter for the other.

Reminding someone to "watch his p's and q's" means to pay attention to the details.