I have another idea as to why people want to try and clean up their flesh. It simply makes sense to the natural mind.
I lost my temper with my mom a few times today and I wanted to despise myself for it and work myself up with shame, guilt, and determination to re-committing myself not to get angry the next time.
The main reason I hated myself was because I misrepresented Jesus. I wanted to tell myself I am a lazy, spoiled human being with everything being handed to me. That I'm ungrateful for Jesus' sacrifice. He did so much and I do so little. I wanted to count out all my flaws again. Grace does not allow this. It does not allow shame based behavior modification, but forcing yourself to accept the fact God loves you in your imperfection. This will set you free if you let it. There is no way this inspires lawlessness. I can't stand being in sin because I am a new creature in Jesus with a righteous nature. I hesitated typing that, but it's true.
Grace is a lot of freedom, joy, and tension.