I don't mind let's players but I bothers me a lot if they go out of their way of approaching the kind of games that are better played for oneself to really experience it and blatantly (though some cases unintentionally i guess?) ruin it for other.
i also think "react" videos are kind of getting stale. i don't mind a try not to laugh since really i'm only in it for the vid comps or wanting to "share laughter with another entity" but beyond that i'll pass. i'm amazed fine bros has gotten so huge and still endlessly producing content. (albeit some of the kids react to things are...interesting. the reactions feel exaggerated though. like it's a gameboy this is where your new fancy stuff came from. stop.)