With both of my teachers there was some form of communication prior to lessons beginning about expectations and I feel that expectations -even if not continually spoken about- maintain a level of clarity between us. That doesn't mean everything's black and white, though. I definitely had some sense of what I was looking for but in some sense, that only landed me there and as I quickly realized it was a right situation for me, that's when it's time to turn over the reigns (with the awareness that I still have to do the work). If I really knew every last bit of what I need regarding my education and how and why, I wouldn't need a teacher. At the same time, I don't think you can describe nice matches in the confines of exactly what every relationship and interaction should be like in order to be a great situation. Everybody is different and since we are all human, it's not necessarily going to be "perfect" in a sterile sense.
What I do know about myself is what it feels like when my circuits are crossed and shorting out and generally my aim has been to avoid this. I think that most teachers are not "bad" teachers, actually, just not right matches. It's a tricky thing to know yourself and have some sense of what you are looking for, while being open to a teacher truly guiding you in a way that you very well might not understand and which actually may lead you to greater understandings of yourself and how you function.
It can be tricky to find the right one(s) and you may very well need to make sacrifices in order to find what you are looking for. There are certain things that I teach and certain levels of proficiency that I expect each of my students to get to which, at this point anyway, if I have a student walk in the door and they are not willing to learn them, then it becomes apparent we are not the right match for one another. That doesn't mean I am not taking into consideration their own goals - but rather that I see what is needed in order to reach them.
I have an adult acquaintance, for example, who for years acts as though she'd like to play the piano and while I've passed along information before, and even given a lesson, I felt there wasn't a true interest in playing. And, I don't mean just a desire, but the willingness to set up a daily schedule that includes piano practice. That is a point which, while it may not describe everybody in precise terms, is true about many people. They might have a floating desire, but when it comes to putting in the work in the necessary ways, there is a disconnect (I'm still working on this myself). So, I had a conversation with this woman again, somewhat recently, and she expressed an interest once again as well as wondering if it were too late for her to play more advanced pieces at some point down the road. I thought that perhaps it was this psychological barrier which is coming across as a lack of interest, and so I sat down and we mapped out a plan. Now, she doesn't live in my State, even, and so weekly lessons are out of the question. But, upon asking her how it was going, she said she has spent some time doing it but while she figured some Christmas tunes out by ear one day, she was very surprised to have to figure it out again the next time she sat down! I told her that this is precisely why daily practice is needed!
I have another adult student who comes to me every lesson as an educator herself, telling me exactly what she feels she wants that lesson and what needs to take place. Honestly, she is a leftover student from years past and one who I would not accept in the same way at this point. A couple of lessons ago she told me about her week -as she loves to do- and in her controlling way she tried to start the lesson when she was ready. Fine, we proceeded along, until we came to a point in the lesson where she said she doesn't understand why she can't just play things! This, after having detailed to me week after week that she doesn't practice and why. I told her that generally playing takes more work than people realize (which is why there are so many "new" piano methods claiming to have you play on the first day ... many people want easy!), and I told her that she couldn't ask that question, at this point. She could ask that question only if she were practicing an hour a day and things still were not coming together. She very quickly stopped talking and resumed focus on our task at hand. I still have some hope for her and for us.
Generally I find that, self-awareness is good, but acting and thinking as though you know everything about how everything should go, not as good. That doesn't necessarily mean you have the right student/teacher match, though.