Note: I have watched through Season 5, and I have no intention of watching further.

Black Mirror messes with your mind. There is no overarching plot because each episode is it's own story. Each episode focuses on a theoretical situation, usually centered around a current or theoretical piece of technology, and all of them portrayed very realistically. It's easy to think of the show's conflicts as immediately rising threats in the real world, with major emphasis on the word "threat." Each episode makes the technology's benefits very clear, giving more credit to its believability, before explaining how it could be used for evil purposes.

Season 1 & 2 - Easily the best seasons. The stories are so harrowing that I couldn't force myself to watch more than 1 episode in a row. Even though I watched these seasons years ago, I still occasionally find myself pondering their implications. There are a couple of rare duds, but most of the episodes are fantastic. These seasons are so good that I wouldn't blame you if you don't watch the rest of the series. 8/10

Seasons 3 & 4 - The original writers probably dropped the series after season 2 because they ran out of material. When Netflix picks it back up, I think it's more accurate to call this a new and similar series rather than a continuation of the original. The seasons have many more episodes, and also many more duds. Granted, even the duds still have thought-provoking concepts, but every 5-15 minutes of substance is dragged out into a 60 minute episode. The series would have been much better if each episode simply goes on as long as necessary to convey the point rather than dragging on to fill a full hour. Plus they are generally "ruined" by relatively happy endings, and the removal of the hopelessness means the formerly gut-wrenching problems don't pack the same punch and they don't stick with the viewer for nearly as long. The result is a show that's much easier to binge (which is Netflix's goal) at the expense of good storytelling. 5/10

Season 5 - Fewer episodes means the writers get to throw out the dud ideas. The episodes didn't drag like the duds of seasons 3 & 4, so it's a step in the right direction. Though it does still lack the punch and lasting impression of seasons 1 & 2. I don't think Netflix is ever likely to return to the roots of a show that's difficult to watch, so this is probably the best we're going to get from now on. 6/10