"You may believe that you are responsible for what you do, but not for what you think. The truth is that you are responsible for what you think, because it is only at this level that you can exercise choice. What you do comes from what you think."
Achievement of your happiness is the only moral purpose of your life, and that happiness, not pain or mindless self-indulgence, is the proof of your moral integrity, since it is the proof and the result of your loyalty to the achievement of your values.