Saying “that was my mistake” out loud feels awful for a second and makes people trust you for months.

The trade is very short pain for very long credit. Admitting an error tells everyone watching that your account of events can be believed even when it is not flattering to you, and that is among the rarest things anybody gets to demonstrate. Most people never manage it, because they spend the moment explaining instead.

Say the four words with nothing attached, no because and no but. Then say what you are doing to fix it. The absence of a defence is the part that registers, and it registers for a long time.