I don't know if they still do it, but there used to be a thing called assertiveness training. A friend of mine took the course and he definitely became more assertive, but I am not sure it was a good thing. It looked to me like he had learned a way to manipulate and pressure others in order to get his own way. Having traveled the AA path too, I would say I have become more principled and willing to live by those principles meaning there are things I won't do and behavior I won't tolerate, not to get my own way, but to live happily in this world and be able to sleep at night. It is more about protecting my values and beliefs than it is about changing anybody else, which is what comes to mind when I hear the word assertiveness.