I'm wrong.

Parents.
Bosses.
Colleagues.
Teammates.
Friends. 

When you don't admit you're wrong, you're modeling for others how to handle disappointments. Model admission of mistakes. This doesn't mean you're saying you had sinister motives - that you meant to hurt someone or cause pain. Or, that you willingly created a problem for someone else. It may just mean that you were simply ... wrong. Saying so gives others the freedom to risk and get it wrong. To own a mistake. To say "that was my bad" without fearing it's the end of the world.