We talked about varying degrees of emotion in class. If it goes to say that we are feeling an authentic emotion when observing a piece, is it not possible we tricked ourselves into feeling it?

I think this is possible.  In class, we talked about the idea of ourselves feeling something as though we weren't feeling authentic emotion, which I disagree with.  I believe that the idea of tricking ourselves into a piece means that we tricked ourselves into believing that what was happening in the book or movie or what have you to be real, and if we are projecting ourselves into the piece, as we usually do, then it just intensifies the experience.  So when we trick ourselves into believing that the experience is real, as opposed to fiction, then we feel real emotion, for just because it is an emotion caused by the realm of fiction, it is still a real emotion.  Now, what degree of that emotion you are feeling will vary between the experience and the person that you are, but that does not change the fact that you are feeling an authentic emotion due to tricking yourself into a false state of reality.