What does the idiom a Monday morning quarterback mean?

Analyzing your mistakes the day after you've made them, generally assumed to come from the act of complaining about quarterback on Monday after a Sunday game.

It's a nonsense phrase used when someone is upset or sad. You pat them on the back and say "There, there." You can also say "there, there, everything will turn out right."

It's a rather rude way of saying "be quiet" - it's referring to tossing something into a trash can, as in "what you're saying is garbage so shut up."

le matin, la matinée