The most frustrating Spotify problem for me is the link between mobile / desktop play queues. I've moaned about it many, many times on the forums and there's a giant thread of people moaning about the same thing, but it's been years without resolve.
Basically, if I don't force-close the Spotify app on my Android before I get my laptop open on the same wifi, the phone will overwrite any play queue on my desktop. I exclusively use Spotify on my phone in the gym. I'll choose one album at a time and play it through while I work out. My laptop is for work - I'll maybe spend 15 minutes every few days queueing 10 or so new albums I want to try. Utterly maddening when you forget to close the app, go to Spotify and you're blasted with gym music and you've lost your carefully curated play queue.
Basically, if I don't force-close the Spotify app on my Android before I get my laptop open on the same wifi, the phone will overwrite any play queue on my desktop. I exclusively use Spotify on my phone in the gym. I'll choose one album at a time and play it through while I work out. My laptop is for work - I'll maybe spend 15 minutes every few days queueing 10 or so new albums I want to try. Utterly maddening when you forget to close the app, go to Spotify and you're blasted with gym music and you've lost your carefully curated play queue.