Re: You don't say
Dare to fall asleep while watching youtube and you will be certain to wake up to a watch history full of utter crap.
I have found, however, that immediately removing crap content from the view history seems to have a positive effect on the suggestions and every now and then the suggestions are mind blowing good, at least on technical topics.
Don't even want to think about how effective platforms such as youtube would be, should our great overlords decide to engage in the business of targeted manipulation disguised under the realms of AI algorithms, so let's just quickly ignore that possibility.