The longer you try to justify the less successful you are at it. Why do some try to oversell what they did/said? Why not quit winners?

Better yet why keep defending what you did/said? Why keep bashing others? Why keep reviving it and nurturing it and feeding it? Why not let it just lie there and die a peaceful honorable death? Beating a dead horse is not something a rational person does. What's to be gained by it?