Is there such a thing as a "neutral" facial expression or, in your experience, do you see facial expressions as either positive or negative?

In my opinion, yes. My sister used to call it "the non-face", as in the face you make when you're not making a face. I find it really interesting though that what feels like a relaxed, neutral expression to me can be perceived as emotional to others. People sometimes ask me what I'm angry about, or why I am sad, when I feel "neutral."