It doesn't matter what you say but how you say it. You may think you said the wrong thing but usually you just said it the wrong way. You can say the same thing but the impact will be entirely different based off your tonality, pitch, and volume. What you think may be a bad thing to say could actually be a good thing to say when you say it correctly.
I broke his heart. We never dated, however. I left him in a bad place. I apologized, and I meant everything from that. But what I did I can't take back. It caused so many bad things to happen. Sadness, anger, happiness, danger. He said he'll think about forgiving me. If I were him I wouldn't. I left him when I heard a rumor. I wish this never happened.