I've since learned that some of my own dissonant thoughts are really just echoes of things that my parents would say. Recognizing that has helped me eliminate many of them. Step one was being my own person, which I could do while I still had those types of thoughts, but step 2 was realizing why the thoughts were there, and being able to move past them.
I still think the best thing I did to improve my relationship with them was move out.