I LOVE LMM and I LOVE Moana, but I absolutely HATED "Shiny" as I thought it so didn't fit with the rest of the soundtrack.
That said, a while later, I saw a live version of the song that was outstanding and instantly loved the song - and I realized, the problem was not the song - it was Jermaine Clement's performance of it that was so annoying.
The song itself is actually great, when it's not sung in a terribly distracting "I'm trying to sound like David Bowie and failing epically" way.
For those who hated the movie version of the song - check it out 12 minutes into this video and see if you like it better this way: