It doesn't matter how good they try to make their recommendation system, they will never know you like yourself. For example, when I go to the YouTube home page, there is a list of categories at the top that it's identified for me. I didn't choose these. I can't add or remove them myself if it's wrong. I just have to hope that I watch the "right videos" and it picks up on a new interest that I have.

But I already know what interest I have! I want to have videos about terrariums on my home page now, not in a week when I've watched enough. This is what I mean by recommendation systems not being good enough. They need to give the user more control over what they want to see, because they can never read my mind. Their recommendations will get even better with that information!