Because of your actions or words, someone is now suffering emotional pain and angry at you. There are not very many situations that are more difficult than this. And there are so many ways to hurt a friend, lover, child, parent, partner, colleague. Maybe you broke a promise. Maybe you lied a little bit. Or perhaps you humiliated someone in front of others. Or used harsh and hurtful words in the heat of an argument that you wish you could take back.
You wish it would just go away. You wish everyone would just forget it ever happened. You wish YOU could forget it ever happened.
But it doesn't work that way. If you want honest and trust-filled relationships, you need to be honest and trustworthy. You need to take responsibility for your behavior and apologize.