Well, in my personal use case, I would like youtube to recommend me is new and upcoming release movie and television trailers. I love watching trailers! They have enough plot in them it's almost like a mini movie or short story. And also I like to know what new shows and movies are coming out so I can watch them later or read the books they were based on. I've subscribed to movie trailer channels and like, watch and upvote them all the time. Yet youtube constantly recommends me other nonsense and I have to direct-search for movie trailers. I haven't trained the alogorithm to show me movie trailers, or maybe youtube is smart enough to KNOW I will now hunt and search for the movie trailers on my own, so they will only recommend me other things? I click "do not show me this" and "I don't like this" on the other videos.

Anyways, it's my personal youtube white whale and I haven't made any progress, so suggestions welcome!