There are a lot of teachers out there who still go by the old school way of teaching, ie think that it is their job to break the student down, rip any ego they have to shreds, etc. There is a difference between being a tough teacher (which is something quite honestly you want) and being an abusive one, and sometimes it isn’t easy to to tell the difference. On the other hand there are ‘nice’ teachers’ who are really nice in lessons,never yell, who also aren’t that demanding, either (kind of like that teacher who is popular because they are easy back in high school or whatnot:).
One thing you may be running into is that you are hitting a different level of teaching , it can be a rude awakening for some when they find out the level of expectations out there when they hit conservatory. Music teachers exist at many levels and kids at some point hit a wall, when my S started studying with the teacher he had through high school he had many of the same feelings you did, realizing the difference between the level his prior teacher demanded and the new one, and you could be running into that. Teachers in high school for example may go over things in detail that a teacher in college expects you to work through by yourself, a high level violin teacher can expect the student to come into lessons being able to play the piece at a technically high level and only want to work on the musical elements, and that can be a big shock, and the expectations can be very different and much higher. With piano, from what I know if it there are certain things that are expected, and yes, some of it can be how the teacher sees things (my S’s old violin teacher claimed his intonation was off, his conservatory teacher and several teachers who worked with him told him that he didn’t have bad intonation, that his old teacher didn’t like the kind of intonation he chose to use), but some of it can reflect the demanding standards any high level teacher will have above a certain level
It could be the teacher is not a fit for you, that is not exactly uncommon, it is why people have many teachers among other things. If your teachers style doesn’t work for you, another one may work better…but one warning, if the problem is you are hitting a wall with the level of expectation , rather than something like the teacher’s way of correcting you (ie yelling), then you likely would run into that with a different teacher,things any high level teacher would look for in terms of technique and such. It is obvious you are unhappy and not feeling motivated, it is really important to figure out why. For better or worse, classical music training is a very exacting, painstaking way of training and if you want to do it there isn’t much you can do to avoid it in one way or the other. Teachers vary, but to be blunt from what I have seen no matter who is teaching, if they are any good as teachers they likely demand you do it certain ways,and what they do can seem like nitpicking, but it is the nature of the beast, for the good or the bad (and I do have some reservations about classical training), to me it is kind of like watching the judging on gymnastics in the olympics when they take a 10th of a point for this, 2 10ths for that, and I look at it and say “they have to be kidding”. :).