Know which conversations need witnesses and which need privacy.

The presence of other people changes what can be said. With a witness, nobody can later invent a different version, which matters when there is a dispute, a complaint, or anything that might need proving. In private, people can admit things, back down, and be embarrassed without an audience, which is what most ordinary repair requires.

Before a conversation you are nervous about, ask which of the two you need. Correcting a misunderstanding with a friend wants privacy. Raising a problem about hours or pay, or anything you might refer back to, is better with somebody else present or a message afterwards.