I've never been okay with the designation of a movie as "so bad, it's good." Filmmaking is incredibly hard, way harder than a lot of people give it credit for, and considering a lot of "so bad, it's good" films are the work of underfunded or novice directors, it just seems cruel to mock the failure of someone's dream.
The other side of the "so bad, it's good" coin are people who enjoy a movie on completely the level the creators intended, yet because they don't understand the workings of the film itself, they mock it, thinking it's bad. These latter films are usually genre-bending comedies, so well-made that intentional jokes strike less-film-literate viewers as moments to mock.
The granddaddy of this kind of "so bad, it's good" film that is actually "so good, it's good," is Rocky Horror Picture Show.
Rocky Horror holds a very particular place in film history, a cult film whose cult popularity has launched it out of cultdom and into mainstream notoriety. The problem with this is that the film was made targeting a very specific audience, an audience privy to the glut of in-jokes and references that it crams into it's relatively short run-time. When taken out of that context and presented to people who are unfamiliar with the cult films that it itself is parodying - and let's be clear here, "Rocky Horror Picture Show" is a straight-forward parody in the vein of "Airplane" - they view the final product as weird-for-weirdness-sake or simply incompetently made.
Let's break down some of these references, so you can decide for yourself how much of Rocky Horror's Humor is intentional - spoiler alert: it's all of it.
The key to deciphering Rocky Horror Picture Show is given directly to the audience in the very opening of the film in the song, "Science Fiction Double Feature." In it, they list or reference a slew of movies. From memory, they mention "Night of the Triffids," "The Day the Earth Stood Still," "Tarantula," "The Invisible Man," "Night of the Demon," "Flash Gordon," "It Came From Outer Space!" "Dr. X" and "When World's Collide."
These films, the genre that will be parodied throughout the rest of the film, include a mix of science fiction, mad scientist stories and British horror, the very same elements that will be blended in the film itself.
We then meet Brad and Janet, played by Barry Bostwick and Susan Sarandon. Here's your first hint that this movie is more than just a low-budget weird flick. By this point, Barry Bostwick - who puts in a hilariously intentional stiff performance - was a Tony Award winner, and Susan Sarandon had worked with accomplished directors John Avilsden, Billy Wilder and was in the midst of filming a movie with Robert Redford. These aren't struggling actors who had to take a bizarre script because they couldn't get a better role. These are accomplished comedians spoofing the stilted dialog and performances that can be found in the aforementioned movies from "Science Fiction Double Feature."
They arrive at Dr. Frank-N-Furter's - his name has got to be the most obvious joke of the movie, and a clear indicator that this movie is parody - castle, the self-same castle used many Hammer Horror (a British horror company) pictures.
Here's where the film is making jokes for very specific audiences. A common moviegoer can be forgiven for not realizing that "lesbian vampire movies" are a full-fledged genre by this point in the '70s, but the movie tackles the concept head-on by filming in the exact same location as the films it's spoofing - where do you think Rocky Horror's exaggerated obsession with sexuality is coming from? It's coming from Hammer's films, which had always introduced sex into the sexless worlds of Universals, but by this point had devolved into films like "Countess Dracula," "Lust for a Vampire," and "The Vampire Lovers." These British filmmakers are tackling British horror, of which Hammer was the biggest name, head on.
In Frank-N-Furter's opening song, he mentions that if they want something visual that's not too abysmal, they can "take in an old Steve Reeves movie." To an audience unaccustomed to schlock pictures, that reference slides away as just another piece of the song. To the well-versed viewer, the line acts as foreshadowing for the reveal of Rocky, Frank-N-Furter's waxed golden body-building creation.
Steve Reeves was an American bodybuilder who starred in a glut of Italian sword-and-sorcery films, most famously as Hercules, where he often wore little more than tiny trunks. He is Rocky's inspiration along with Charles Atlas, a body builder who is also later named by song, famous for appearing in comic book ads offering to beef up lanky teens.
Soon, we get a glimpse of Meatloaf as Eddie, a motorcycle riding character reminiscent of Harvey Lembeck's Von Zipper gang leader from American International Pictures' (a company known for it's schlocky b-movie output) beach movies of the '60s.
Dr. Scott - or as the nonsensical third-act reveal that is so common in odd sci-fi films Dr. Von Scott - is introduced to aid the transition from the Hammer Horror parody to the classic sci-fi parody. This genre-bending mash-up makes the movie feel like a...wait for it...Science Fiction Double Feature.
If there is ever any doubt to if this film is a parody, just fast-forward to Barry Bostwick's hilarious "It's as if we're glued to the spot!" reading and arm-movement.
Again at the end of the film, they directly call out the films they parody by setting the finale in front of the RKO logo - RKO being one of the original big Hollywood studios and the makers of King Kong, which Frank-N-Furter names in song and Rocky and Frank-N-Furter reenact as the film ends. The reveal that the characters are actually from the galaxy Transylvania instead of the horror-locale Transylvania completes the double feature transition and places the film firmly into science fiction territory.
And so we're brought back to the brilliant framing device of "The Criminologist" mimicking bookended films like "The Cabinet of Dr. Caligari" and "Bride of Frankenstein" and even old EC horror comics, who treat the adventures within as stories told to the audience from an outside viewpoint.
This is basically a long way to say that you need to check your framework before analyzing a movie, and a little context can go a long way from re-framing a movie from "so bad, it's good," to just straight-up "good."