I love movies with big ideas. I would much rather a movie go big with a new or challenging philosophy or concept and not be able to follow through than a movie that plays it safe with a story or plot that we’ve seen a hundred times before.

But then again, there’s nothing more painful than seeing a good idea totally wasted. Or worse, a movie that so over-commits that it crashes and burns through its own misdirected vigor. Such is the case with Downsizing, Alexander Payne’s new movie, whose honest attempts at satire and social commentary end up as a disastrously off-track study in political correctness and message-y schlock.

Downsizing’s first half-hour is encouraging, as Payne (and co-writer Jim Taylor) sets up a truly intriguing concept: science has developed a technology to shrink humans to one-twelfth of their size, which allows them to live in a much more economical way, not to mention provide a smaller carbon footprint—a benefit to both the planet and to our way of life. The way this premise is set up is clever, charming and funny. Matt Damon plays an ordinary guy who is attracted to the concept of “downsizing” because his life has hit a proverbial rut and he thinks it would make his wife (Kristen Wiig) happier. He decides to learn more about it, talking to people who have “gone small” and visiting Leisureland, a “small community,” so he can see how people who’ve gone through the process live. I was so absorbed and interested in the whole concept, I was 100% on board. I was excited to see where they would go with it, once he actually goes through with the downsizing process. More comedy and cleverness would follow, right? Tons of sight gags and maybe some “small bias” jokes thrown in to remind us of a moral of the story, right?

Oh, if only.

Nope, once the movie moves past the novelty and exposition phase of the “downsizing” idea, the jokes run dry pretty quickly as the movie takes an abrupt and, quite frankly, annoying turn and becomes a message movie. I understand that Downsizing was already a message movie at this point, with the concept of “downsizing” positing a way to save the planet (assuming all humans would buy in) by helping with overpopulation and global warming. That was the clever way that Payne and Taylor melded comedy with concept. And I would have been happy if they had left it at that. But instead, the movie veers way off course and becomes a movie about social inequities, racism and class structure—even immigration. Seriously? One minute, this movie is a charming lark with subtle undertones of “save the planet”, then turns into a graphic, depressing and dark tale of human suffering—not even done well.

Downsizing literally feels like two different movies and the second one is not only dreary, but lifeless and incoherent. It continues to drag on and on, getting further mired in its own self-awareness. Every bit of good will it had built up in the first half hour is obliterated by its overindulgent and self-serious storyline at the end.

Nothing ends up being good here, including Matt Damon, whose chronic blandness defines everything about this movie. Christoph Waltz is wasted, as is a great initial concept that becomes nagging and even insulting.

Skip Downsizing, it’s easily the worst movie in a very crowded holiday movie season. That’s no small feat.