I had, for the most part, good teachers who knew damn well that it is not just about subjective interpretation and that you have to fucking back up your claims. Sadly some teachers - and, accordingly, tons of students - think it is. The concept of proof and argument in the humanities style is not something that a lot of people seem to understand (or teach) and it is kinda sad. That said, if you can genuinely and thoroughly back up your interpretation, teachers with at least a modicum of sense won't penalise you - however, sometimes you have to work harder to write a good essay than if you agree with the teacher. If you present it as just a subjective interpretation, they have much more room to penalise. People can see studying literature as too subjective, often, and leave out the focus on evidence that belongs to it. (True of some people who write criticism professionally too, unfortunately.) I find also some teachers would discuss interpretations without discussing why they came to them, or at least have a strong focus that way -- which is interesting in terms of learning about the literature, but of much less use in learning about literary criticism, which is what one is supposed to produce. I learnt how to write essays by reading books and books of literary criticism - it wasn't taught enough in class. First INTJ I met was my favourite English teacher - though I did not know mbti at the time. She was freaking awesome. I do hate some of the books I have studied, though. Margaret Atwood can go hang herself, as can Robertson Davies. Yeesh.