Words stain like red wine on your couch and you try so hard to erase it out but remnants will remain and even when you no longer see it, it will always exist in your mind and you will remember, memories and feelings will rush back and you wish you could remove that stain-- that scar that won't ever disappear in your mind as easily as you removed that red wine.
Be careful with what you say when you're angry or in pain. When things cool down and you say, "you didn't mean it", it becomes hard to believe it because everything was said and done and you can't take that back. Forgiveness can happen but remember that they won't forget it, you permanently scar someone.