What makes a movie "so bad it's good," instead of just bad?

Midnight movies. Guilty pleasures. Cult classics. We have lots of terms for films that are so bad, they're good. But why do we really love terrible films, sometimes more than good movies? And why aren't all bad movies wonderfully bad?

January is the "guilty pleasure" paradise. Just in the past few weeks we've seen the release of Legend of Hercules and I, Frankenstein — two prime examples of the "so bad it's good" movie. Past Januarys brought us the splendors of Hansel and Gretel, Witch Hunters, Season of the Witch, and Legion.

What all of these movies have in common is a certain amount of "I can't believe they went there," combined with a mostly non-ironic insanity of the performances and dialogue. Cheesy visual effects, logic-defying plots, flubbed story beats, mad set pieces. A really great bad movie makes you fall out of your seat laughing and cheering for the awfulness.

But just last month, we witnessed the release of 47 Ronin, which was a perfect example of a movie that's just bad, rather than "so bad it's good." 47 Ronin had a lot of the right ingredients, including a nonsense plot and Rinko Kikuchi as a demon lady who ate sashimi with her hair in a lesbian seduction scene. But it never climbs out of the Unfunny Valley.

What makes a movie "so bad it's good," instead of just bad?

It's like watching someone get hit with a pie: possibly hilarious, or possibly just kind of boring and sad. Possibly depending on the type of pie, like cream pie versus steak-and-kidney pie.

So what are the differences between good-bad and bad-bad? To some extent, it's like asking "what make a joke funny?" Something is funny because it's funny, and you can't analyze it. But there are several factors that come to mind, most of them having to do with whether a movie is bad, or extreme, enough to climb out of the Unfunny Valley between "good" and "so bad it's good."

Let's break them down.

Acting: There's a reason why Nic Cage has become the patron saint of wonderful badness, to the point where he made Abed's brain explode. A really great bad movie, like Roller Blade or Island of Dr. Moreau, features inexplicably terrible performances, where people appear to be trying to win a shouting match with a walrus that's in the next town over. Great "bad movie" performances are operatic and shameless — as opposed to the subdued, "forget you saw this" performances people like Keanu Reeves and Paul Bettany tend to do in their bad movies.

Pacing: A really great bad movie should be under 90 minutes, most of the time. Or if it's closer to two hours, that should be because someone on set suffered a drug overdose and they just kept filming. Our favorite bad movies have a frenetic, "throwing everything out of the speeding ambulance" pace that doesn't ever bog down. Although to be fair, a ton of so-bad-they're-great films have the common "B" movie problem where the pace lurches from catatonic slowness to speed-addled hyperness — many bad movies only became truly great with the invention of the VCR and the fast-forward button.

What makes a movie "so bad it's good," instead of just bad?

Paint-your-van awesomeness: Again, it's a matter of committing to the madness and going all the way, as opposed to stopping halfway in the hopes of climbing to mediocrity. The sparkly, disco-in-hell costumes are a huge reason why The Apple is so fantastic. The bizarre VFX and flaming visuals are what make Drive Angry 3-D such a wonderful mess. A great bad movie will make your jaw drop even with the sound off.

Quotability: It's dialogue like, "While you were still learning how to spell your name, I was being trained to conquer galaxies" that makes Battlefield Earth such a source of endless joy. A regular bad movie can have banal dialogue, but a good-bad movie tends to have dialogue that would make George Lucas look like Harold Pinter.

Transgressiveness: One reason we love bad movies is because they break all the rules and make our skins feel just a little bit less constricting. So a really great bad movie is one that contains some bizarre transgressions, and pushes the limits of what you'd consider watching with your grandparents.

Lack of respect for the material: Only a few big franchises have really managed to release movies that are really wonderfully terrible — Batman and Robin comes to mind, and maybe Star Trek V and Octopussy. But those latter two are debatable. You need to have total lack of regard for the material you're working with, and at no point should ever sit and worry about "what the fans will think." You can still get terrible movies that treat their material with a minimal amount of respect, but they tend to be dull rather than mind-blowing.

What makes a movie "so bad it's good," instead of just bad?

Freudian slips: The best bad movies reveal something profound and embarrassing about the psyches of the people who made them, and to some extent about all of us who choose to watch them.

Budget: By and large, a really great bad movie has a low or medium-sized budget, because the more money involved, the likelier it is that studio execs were standing around trying to reel in the director's "vision" and make the whole thing slightly less insane. Most of the time, when the budget gets over about $100 million, you'll end up with a boring slog — it could still be tasteless, like The Lone Ranger, but not wildly tasteless. That's what ailed 47 Ronin, too — it kept almost going off the rails in an entertaining way, but then you could tell that sense and reason had prevailed, resulting in a dull mess rather than a fun mess.

Lack of irony: Finally, you can have a certain amount of winking self-awareness in a wonderfully terrible movie — it worked for Mortal Instruments — but past a certain point, a movie that makes fun of itself doesn't leave enough room for the audience to make fun of it. The best terrible movies are usually somewhat unselfconscious about their terribleness, and we love them all the more for their sincerity.