Sometimes you heard something once, and do not want to hear it again (yeah, we can hide tracks on mobile, but not on the desk, desk version only can hide random tracks), but after some time you might hear it again, for example, if listening to one of those musicians, or just forgot about a playlist you already heard. Me personally, don't want to waste time on that and i would appreciate a feature to hide tracks, albums & playlists completely + closed personal hidden playlist (like watch later on Youtube). On the other hand, if you dont want to hide tracks, but might forgot if you listened it before, i'd suggest a feature to see your own play count of tracks or a feature to mark as listened (a check or playlist, that could mark as listened). One more suggest is to make listened before tracks with different color. Or just dislikes would be much appreciated.