How could you?

How could you sleep peacefully at night knowing that you're hurting someone's feelings? How could you sleep peacefully at night knowing you broke someone's heart? How could you sleep peacefully at night knowing you ruined someone's life? How could you say that harsh word straight to my face? How could you be so cruel? Did I do something wrong to be treated like this? Did I? If I am, then I'm so sorry I didn't mean it.