Obviously, I have no idea of this is true or not, but I wonder if it could be actually because nobody really cared about your behavior when you were a kid. Nobody held you to a high standard. But effective parents do set limits. It creates an atmosphere of trust that when you get out of hand they will be there to help you stay in control. And you are responding to that. So I think it's great.
It would not work at all for me. My father was very inconsistent--passive and easy going and then poof all of a sudden angry and not in control. Often this had nothing to do with my behavior, but I always thought it did. So now anger from therapists/doctors/anyone in authority scares me to death.
It's sounds like your new therapist is pretty effective at adapting her style to the needs of her clients, and that is awesome. And congrats on going back to medical school. If you ever end up being my doctor though, don't yell at me. I hate that