Siblings know exactly which words start a fight. Knowing them and not using them is the grown-up part.

Growing up beside somebody gives you a map of exactly where the wires are. You know the nickname, the comparison, the old failure that will land hardest, because you were in the room when it happened. Having the map does not make using it clever; anyone with the same childhood would have it.

Notice the moment you reach for the thing you know will work. Choosing something else, even while you are genuinely furious, is the part that keeps you someone your brother or sister can trust. The fight ends either way, and only one version leaves a mark.