A lot of people -including me- LOVE creating new playlists on Spotify and lots of them do it by specific genres or etc. When we wanted to add a song to our favorite playlists, we cannot be sure if we used it before in another playlist or not. I know it seems like an unnecessary problem but it bothers a lot.
So I think about something. When we click the three dot right above the song screen, there should be an option like "See The Playlists Which The Song Has Been Used/Put"[I'm not good at finding catchy names :)] which shows us where did we put the song or did we put it in any playlists.
This can make the app more useful and adding new things easier I think!