Most jazz...a great deal of it seems to be musical masturbation - look how much I can do with the rules of music, melody, and harmony. Except a great deal of it is not musical, melodious, or harmonious.
Metal. Turgid riffery for its own sake.
Rap/hiphop - garbage.
Yes, I'm well into the older end of the old fart spectrum. Getting there has taught me to like what I like and, largely, disregard everything else.
On the other hand, I'm surprised by a few things I like now - Alison Krauss, for example. As a prog-head in the past, it would not have been on my radar at all.
Now, it's almost anything prog-like that is off the radar...and I'm starting a Carpenters tribute!