Some mistakes hurt. Some mistakes should hurt. So you remember them. So you avoid them. Pain is a very good teacher. Not nice, but fair. Strict but treats everyone the same. And the end of the it passes and leaves you changed. And some kinds of pain will be part of your life forever, every decision you make in future will bear the mark of that pain.
Well time to live up to this. Never ever start something, that you do not intend to finish it. Waste of time. Waste of pain. Never again.