Spotify generates a playlist for you called discover weekly (also some others for discovering music, but I don't really know about those, they seem seasonal). The whole point of this playlist is to introduce you to music you don't know and could potentially like.

But for some reason they decided to include music that already is in your library. Yeah no shit I'm gonna like music that I regularly listen too. Other than that they also often play music from artists in my library, just not the songs I actually have saved. So, that's zero effort and requires no algorithm at all.

Now they DO actually try to guess what music I like quite often. Many songs or artists I haven't heard before get recommended. It's just on the other end of the musical spectrum from my liked music way too often.

The weird thing is... IF I take a pause and only open this playlist about once a month it actually seems decent.

I now feel like discover gets influenced by listening to discover, just not in the way it''s intended too. There are like and dislike buttons and I actively use them. But I think hitting the dislike button on a song still gives it a positive rating (higher than a song I haven't listened too) while it should actually get a lower score than neutral.