For me:
Bob Dylan.
I just don't get it, no matter how hard I've tried. Sure, the lyrics are interesting, but except for a handful of songs, they mostly bore me musically.
And although I will listen to a few of his songs if they happen to come on the radio, I have never willingly put on a Bob Dylan song or album.
****
David Hockney
Seriously, what is this crap?
I've seen better art on the walls of a middle school hallway.
****
What are yours?