Someone asks what time it is. You glance up at the Moon, pause, and say "quarter to eleven, maybe eleven".
Then you're right.
The Moon keeps a schedule. Full moon rises at sunset, peaks at midnight, sets at sunrise. First quarter runs six hours ahead of that, third quarter six behind. New moon shadows the Sun exactly.
The bright edge points at the Sun; always, no exceptions. So the Moon tells you where the Sun went. Fifteen degrees below the horizon is one hour. Forty-five is three.
Learn it in twenty minutes. Spend a week checking yourself against your phone before you try it on anyone.
And when you do, give the range. "Around eleven, within half an hour". Precision you haven't earned gets caught. Precision you have, with the uncertainty named out loud, lands like you've been doing this your whole life.