Nirvana - didn't "get" it at the time, and still don't 20-odd years later. My wife loves 'em though - and I do admit that the riff to teen spirit was damned catchy.
Fleet Foxes get filed under WTF for me too. Though, I'm generally suspicious of music that my Mum "loves".
I'd always put Pink Floyd in the rubbish bin, but that changed after I went cycling on acid with a tape of Relics for a soundtrack. Couldn't imagine listening to them now, but I couldn't imagine dropping acid either.
That said, I may just dig out Fat Old Sun for a spin - a lovely song.
And for what it's worth I reckon Jim Reeves' version of He'll Have To Go is a serious MF of a tune: