When you snap at a younger sibling, owning it out loud shows them strength and humility can live in one person.

A younger sibling learns what an apology looks like from whoever is above them, and mostly they are watching whether the person who was wrong can say so. Owning it out loud teaches something no instruction will, which is that being strong and being sorry are not opposites. It also tends to lower the temperature immediately.

Go back and name what you did, without adding the reason you were stressed. Say it in plain words and let it be brief. Then move on rather than turning it into a long conversation about yourself.