While I agree that "good" art "sits just outside of what we expect", I must play devil's advocate here and say that the uncanny valley of CGI/AI/... also "sits just outside of what we expect".

So there must be more to it.

You might like the book Emotion and Meaning in Music - it starts from some outdated psychological ideas (that emotions are only intensity and that we assign positive/negative valence post-hoc) but ties that to early information theory and makes a really compelling theory of music that's all about the interplay between expectation and surprise, across both the physical harmonic ratio stuff this paper talks about and the cultural associations too.