I couldn’t keep paying for it in good conscience when they killed the original Play Music app and along with it: their awesome selection of curated playlists, the best library organization I’ve seen before or since, and the critical one, the ability to upload your own music that wasn’t available already. I just can’t stand YouTube as a music organization platform.

Edit: Oh! And not to mention the I’m Feeling Lucky button that somehow no one else has managed to replicate.