I haven't seen most of them, haven't even heard of some of the shows. Like all lists of this type, there's probably a handful of "controversial" entries that are just meant to generate discussion (they included an episode from the last season of GoT.)

But I do agree with the top pick.

Shows like Simpsons & Seinfeld are obvious choices for jumping in and watching the one episode.

Shows like Community & Parks and Rec help to know the characters a little bit, but similarly you can jump right in.

Then you have shows like Atlanta & Bojack where they have traditional story episodes, and then special one offs. The episode selected is the one off, so you can watch that and have all the context needed for a great episode.

However on that same note you can have the Leftovers and the episode they choose is wild. It is arguably a one off, however I don't think you could just watch it alone.

We also have heavy story episodes like Succession, but really what makes the episode memorable is the acting. You'd be lost with some of the story threads, but the reason they chose the episode they did is that is displays a raw human emotion that I think everyone can understand.

And then finally you have Breaking Bad type episodes. You need the full context. Not that it wouldn't be good without it, but is the connecting piece of so many different things you'd be missing too much without it.

So to answer the question... Yeah, it's tricky.