I am afraid to keep listening to the Great Fugue. I would come to like it, whether it is great art, or whether it is pretentious garbage. That would not rule out any of my theories.

How can I figure out which it is before listening to it repeatedly?

Can't believe I didn't notice this. Who cares man? Caring about whether its "pretentious garbage" or "actually complicated hard to like art", is just as silly as liking something cause you think it makes you cool to like it. That;s not the point. The question is will you dig your time here more, have more musi-gasms, if you keep listening, or less.