Sometimes the most accountable sentence is “I don’t have a good excuse.”

Stopping there takes more nerve than explaining. Every instinct pushes you to produce something, because a bare admission leaves you standing in the open with nothing to hide behind, and most people will accept almost any reason just to end the awkwardness. Refusing to offer one tells them you are not going to manage them.

Try it once, where it is true, and then say what you will do next. No build-up, no softening. People trust that far more than they trust whatever the excuse would have been.