As far as The National Anthem, I didn't like it either. I thought the general concept was interesting, but the way it was conceived was crude and largely unrealistic in terms of how the situation would unfold. I've never gone back and rewatched it.
SPOILERS AHEAD FOR LOCH HENRY, FIFTEEN MILLION MERITS, WHITE BEAR & SHUT UP AND DANCE
The problem with Loch Henry, for me, is that it focuses on two genres I have no interest in - True Crime and Horror. I never watch this kind of stuff. I know the episode was ultimately targetting both in a negative way, but 98% of the episode was just played straight, with the final few minutes making the point. The balance was too far towards a basic, linear narrative without any elements that interested me. The other problem I have is that the 'morals' of the episode - that the obsession with true crime stuff is ghoulish and entertainment bosses are greedy pieces of shit who only care about money and ratings - are nothing new or thought-provoking. For me it was like, yeah, and? This is hardly groundbreaking social commentary. I'd be worried if people need those things spelled out to them at this point. There's also incredible hypocrisy when this tale is being told via Netflix, for obvious reasons.
Fifteen Million Merits basically told the same story, but replacing true crime with reality TV. What made that episode interesting to me was the dystopian future it was set in. Throughout that story you see how the people involved have had their lives warped and degraded by the obsession with reality TV, and how even in this grim world they're a part of, they're still hooked on reality TV as it's all they have left to get enjoyment out of. It also targets stuff like microtransactions and wasting money on stupid stuff like avatars, fake nonsense that gives a brief dopamine rush but provides nothing meaningful.
Loch Henry doesn't really go into the same depth in any way. It's just played as a straight horror/thriller/mystery until the final few minutes, and even that left me perplexed. I just don't think it's realistic in the slightest that a guy who has just lost his mother to suicide, has a girlfriend missing/presumed dead, and has just found out his parents are sadistic murderers would have gone along with creating, producing and being a central part of this documentary. Especially within what seems like the span of a few months. I couldn't really suspend my disbelief when it came to him being on stage collecting an award for this, being interviewed for the documentary, etc. There's no indication his girlfriend was ever found either, and you're telling me this guy wouldn't be implicated in some kind of police investigation? I don't buy it. It didn't make any sense to me. It just felt like poor writing.
So yeah, the idea that this episode was some kind of great insight into modern obsessions with true crime and entertainment left me cold. They've done it before, and in my view done it better - White Bear is another example of the same basic premise, and this actually did have some elements of horror in as well, but was executed in a much more intriguing way. The thing that White Bear and Shut Up and Dance both did well is that they made you sympathetic towards the main character, only to find out at the end that said character had sone something really heinous, putting you on the other side of the fence and putting the episode in a completely different light. The twists in both were genuinely surprising and thought-provoking, whereas in Loch Henry the "twist" was pretty mid as I didn't really have much connection to the main charatcer or his parents.
If they don't have any new ideas I'm not sure if there was much point in bringing the series back.