>>213908865 (OP)
Bleak. Dystopian. Most episodes depict the world we're creating for ourselves. Very few are slightly more hopeful.
In Days of Olde, there was a book of Japanese science fiction stories called, unimaginatively, _The Best Japanese Science Fiction Stories_. One of the stories was about a pair of con artists that tricked people into believing they were transporting them into one of two divergent realities, but of their own choosing. Of course, they explained that the alternate reality would be very like the one they come from, at first, but that it would slowly, over time, diverge more and more from their base reality into the reality they described.
At the end of the story, the con artists realized that most people, when offered a choice, turned down living in the peaceful, beatific, post-scarcity reality for the dystopian, horrific, post-war reality because it represented struggle, and was more interesting. Then they realized, because none of these people were actually being transported into any alternate reality, what it was they were actually doing. They were convincing people that the reality they were living, the only reality, was headed toward a dystopian, horrific, post-war hellscape that they likely wouldn't survive. They were populating the world with people who thought it was going to be destroyed in their lifetime, and who had actually chosen this fate for themselves and everyone they know.
Black Mirror is like that. It's literally the name of the thing. Most of the events and technologies described in the show will eventually come to pass, in some way, and it will be horrifying.