The correct way to say the expression to watch your P's and Q's is to mind your P's and Q's. The expression to mind your P's and Q's means to be careful or cautious. The P's in the expression to mind your P's and Q's refer to the pints and the Q's in the expression to mind your P's and Q's are said to be the quarts.
The expression to mind your P's and Q's is believed to have originated from the fact that the publican chalks up, or writes on the slate, the drinks he has supplied to the customers. This is to make the customers aware of the quantity of the drinks which have been consumed by each of the customers, lest they end up with unexpectedly large bills. It is also believed to be abbreviation of the expression to mind your please's and thank you's, which are two of the most polite words in the English language.
The expression to mind your P's and Q's is believed to have originated from the fact that the publican chalks up, or writes on the slate, the drinks he has supplied to the customers. This is to make the customers aware of the quantity of the drinks which have been consumed by each of the customers, lest they end up with unexpectedly large bills. It is also believed to be abbreviation of the expression to mind your please's and thank you's, which are two of the most polite words in the English language.
