Greendale Community College was the central location on Community and an incredibly confusing place. Improbable, if not outright impossible, things happened there daily, and while much of the history of the college remains undiscussed, the major catalyst for the most absurd shenanigans seemed to be Jeff Winger's study group. And the answer as to why may lie in a completely separate series: The Good Place.
The first episode of The Good Place found a group of recently deceased souls arriving in what is essentially a non-denominational version of Heaven. They each believed they were in the Good Place due to a clerical error and sought out the help of Chidi, a moral philosopher, with their goal being to become worthy and not get sent to the Bad Place.
What Eleanor and her friends eventually discovered, however, was that they were already in the Bad Place and Michael, the architect of the plan, was actually a demon who created this experiment to torment the three of them alongside another damned human soul named Tahini. Michael even went so far as to steal an actual Good Place operating system AI named Janet to make the whole thing seem as real as possible.
Part of what made the fake Good Place neighborhood work was that it responded to the needs of its residents, an attempt to make it as marvelous an afterlife as possible. But throughout, there were little details designed to torment the four humans in mental and emotional ways. Essentially, Michael set up an environment that would allow them to torment themselves without even realizing it, which was a departure from the normal Bad Place torture methodology.
Well, if fans take a step back and look at Greendale through the lens of being part of the Bad Place, all the absurdity starts to make a lot more sense. Everyone involved in Winger's study group was guilty of something in their lives, from the mundane all the way to the horrifying. And with that being the case, it wouldn't be a surprise to find out that they had all been sent to the Bad Place alongside Eleanor and her friends.
Greendale Community College could easily turn out to be another experimental Bad Place neighborhood, as there were plenty of times that it seemed like a place designed to torment the original seven members of the study group. Possibly the biggest clue that Greendale was designed as a portion of Hell, though, was the fact that they couldn't seem to escape it. The group was at that school for what seemed like forever and just kept getting pulled back in when they did try to leave. The prime example of this was the fact that Jeff Winger ended up becoming a professor at the school, cementing his eternal torment.
There's also a strong comparison to be made between Michael and Dean Pelton. Michael started as the demon tormentor of Eleanor, Jason, Chidi and Tahani, but he ended up bonding with them and becoming part of their group. If Greendale was a Bad Place experimental neighborhood, the demon tormentor in charge would've been Dean Pelton, and like Michael, he ended up bonding with the study group and becoming one of them.
Greendale was a place that kept devolving into chaos, anarchy and outright post-apocalyptic nightmares, and the reason why was never touched upon. Some fans may be able to look past all of that and just enjoy the show for what it is, but so much about Community starts to make sense if you consider the idea that Greendale might literally have been in Hell.