Forgive the version of your mom that was exhausted. She was running on empty and still made dinner.

People are easier to forgive once you can see what they were carrying. The mother who snapped was also the one who got dinner on the table while running on nothing, and you were a child, so you saw the snapping and not the arithmetic behind it. Understanding her tiredness is not the same as saying everything was fine. It just lets you be angry at the situation instead of only at her.

If you want to, try picturing one bad evening from her side this week. No conversation required. You can also leave this one alone if it is too close.