Once you have identified with some form of negativity, you do not want to let it go, and on a deeply unconscious level, you do not want positive change. It would threaten your identity as a depressed, angry or hard-done by person. You will then ignore, deny or sabotage the positive in your life. This is a common phenomenon. It is also insane.
We're all looking at the people around us, the people who have gone before us who have succeeded in recovery and have long-term sobriety and they are an illustration for us of how good it can be.