Snapping at people on one bad day doesn’t make you mean. Doing it every day without noticing might.

A single sharp reply is usually just a bad day leaking. Tiredness, hunger, something that happened earlier and had nowhere to go, and the person in front of you catches it. That is ordinary, worth apologising for, and not evidence about your character. The difference is pattern: a habit you no longer notice has stopped being a bad day and become a way of speaking.

Ask someone who sees you daily whether it is a pattern, and listen to the answer rather than defending it. If it is, repair the one in front of you first. Short apology, no essay, then watch for the next time.