I'm a Doctor, Not a Placeholder
Characters have their limitations. Well, let's just hedge our bets and say well written characters do. Often, when a character has run into something they don't have the skill or knowledge for, they remind the viewers of that in a stock phrase that is almost always worded as: I'm an X not a Y. With X being their profession, and Y being whoever would be better able to do the job that they are having difficulty with.
Another variant is to have the character use this stock phrase to explain that they find something morally repugnant. In this case, Y will be something along the lines of common criminal, pervert, or murderer.
The most famous example, and thus the Trope Namer, is Star Trek's Dr McCoy—but the earliest example we have so far is from 1863, making it not only older than Star Trek but Older Than Radio. Note that DeForest Kelley, contrary to popular belief, never prefaced his statement with "Damn it, Jim" or some variant thereof; he never swore on the show, given that it aired in The Sixties. He did swear up a storm in most of the movies, however, so parodists naturally combined his potty mouth with his catch phrase, to great effect. (He never actually used his Catch Phrase in a movie until the reboot).
- In The League of Extraordinary Gentlemen, Dorian Grey exclaims at one point "I'm an immortal, not a gazelle!"
- Older Than Television: In 1933 Philo Vance detective movie The Kennel Murder Case, the doctor is called to the scene of the crime, questioned by bystanders, and replies "I'm a doctor, not a magician". A few minutes later, he pronounces a man to have committed suicide and is reminded he's supposed to look at the body, to which he replies "I'm a doctor, not a detective".
- Team America: World Police has the protagonist insist "I'm an actor, not a spy!"
- This even appears in The Movie of Lost in Space, when Dr. Smith says "I am a doctor, not a space explorer." It's probably a deliberate reference to Star Trek - the two parent series were Dueling Shows, back in The Sixties.
- In Who Framed Roger Rabbit?, R. K. Maroon protests: "You got it all wrong, Valiant! I'm a cartoon maker, not a murderer!" Valiant: "Everybody's gotta have a hobby."
- From The Hangover: "I'm a doctor, not a tour guide!"
- From Monsters vs. Aliens but reversed: "I'm not a quack; I'm a mad scientist!" (Dr. Cockroach)
- Naturally, as an Affectionate Parody of Star Trek, Galaxy Quest includes an example of this, in one of the film's most famous lines: "We're actors, not astronauts!"
- In the 1956 sci-fi classic Forbidden Planet, Robby the Robot responds to Alta's request for a new dress with a deadpan "Again?". The implication seems to be that 'he' is a hyper-advanced super robot, not a dress-maker.
- The Man Who Would Be King:
Billy Fish: [On being offered a horse to escape the lost battle] Gurkha is foot soldier, not cavalry. Then he runs to confront the entire army and dies a warrior death.
- A Hard Day's Night: Ringo is a drummer, not a wet-nurse.
- Prince Roger: Inverted with Dobrescu's repeated claims he's a shuttle pilot, not a medic. Later it is re-inverted, when Dobrescu has to start working on the Mardukans and complains that he's a medic, not a xeno-surgeon.
- In Death Star, Doctor Uli Divini is ordered to make routine checkups and says "I'm a surgeon, not an internal meds doctor!" He has to do it anyway.
- Twenty Thousand Leagues Under the Sea (1869): After Captain Nemo Kicks The Cachalots with the Nautilus, he asks Ned Land his opinion:
"Well, sir," replied the Canadian, whose enthusiasm had somewhat calmed; "it is a terrible spectacle, certainly. But I am not a butcher. I am a hunter, and I call this a butchery."
- Trope Namer is Dr. McCoy from Star Trek: The Original Series.
- And proudly continued by the Emergency Medical Hologram (EMH) from Star Trek: Voyager who was in fact an actual placeholder.
- McCoy twice had this inverted on him when he tried using it (in both cases McCoy was trying to get out of an assignment):
Kirk: "You're a healer, there's a patient. That's an order." (The patient in question was mostly made of rock, and what McCoy wasn't was a bricklayer.)
Scott: "Now, you're an engineer."
- The EMH from Star Trek: First Contact almost gives the trope title with "I'm a doctor, not a doorstop."
- Amusing anecdote: Robert Picardo got the part of the EMH by ad-libbing "I'm a doctor, not a night light!" during his audition.
- Amusing fact: he didn't know that was McCoy's catchphrase—he just thought it sounded funny.
- If you shoot him in the game Elite Force, he says "I'm a doctor, not a bullseye."
- Lampshaded by B'Elanna ("I'm a Doctor-" "Not an engineer, right,") and flipped around by Tom. "I'm a pilot, Harry, not a Doctor!"
- The justification variant is frequently abused by Tuvok, who seems to feel compelled to begin any and every sentence or explanation with "I am a Vulcan."
- Amusing anecdote: Robert Picardo got the part of the EMH by ad-libbing "I'm a doctor, not a night light!" during his audition.
- Even Bashir gave it a shot in Star Trek: Deep Space Nine's anniversary episode "Trials and Tribble-ations".
- Subverted in the Saturday Night Live episode that William Shatner hosted. In one sketch with the Enterprise now a restaurant, one of the customers starts choking on his food. Shatner, as Kirk, tells "McCoy" (Phil Hartman) to help him. "McCoy" responds, "Dammit, Jim! I'm a doctor not a-- Oh! Oh, sure!"
- However, it was played straight in the earlier "Last Voyage of the Starship Enterprise" skit: Dan Aykroyd as "McCoy" deadpans the line "I'm a doctor, not a tailor, dammit!" and gets a huge laugh.
- Inverted for laughs on Rowan and Martin's Laugh-In by DeForest Kelley himself: "I'm not a doctor, I'm a convicted murderer!"
- There's another parody example in Bobby Pickett and Peter Ferrara's Star Drek. Mr. Schlock advises Captain Jerk to wait for further plot complications before taking action; when Jerk asks McCoy his opinion McCoy replies "I'm a doctor, not a scriptwriter!"
- A 'morally repugnant' example in "Broken Link", when Garak tries to convince Worf to stand by and let him commit genocide. Worf responds with "I'm a warrior, not a murderer!"
- It was such a trope of McCoy's that it had to be in the 2009 revival. "I'm a doctor, not a physicist!" (Well, his understanding of the physics Spock suggested seemed okay....)
- An episode of The Fresh Prince of Bel-Air had Will, Carlton and WilliamShatner get high off of a leaking laughing gas tank at the dentist's and start acting like Star Trek characters; after Shatner addresses Will as "Bones", he responds "Dammit Jim, I'm a black boy from Philly, not a doctor!"
- Monk has a few good ones. This one from "Mr. Monk and the Critic":
Captain Leland Stottlemeyer: Where the hell is Randy?
Natalie Teeger: Oh, I sent him out to get a newspaper.
Captain Leland Stottlemeyer: [looks at her incredulously] You? You, you sent Randy out? Well, who are you, the new police commissioner?
Natalie Teeger: The morning edition comes out at midnight! They're gonna review Julie's play!
Captain Leland Stottlemeyer: For the love of god, he's a police lieutenant, not a bellhop! Though maybe he is.
- In "Mr. Monk and the TV Star," when Monk and Sharona arrive at a crime scene at a major star's house, Sharona is focused on her teeth, and Monk tells her, "Sharona, this is a murder scene, not a high school dance."
- Stargate SG-1 provided a variation of this trope in "Deadman Switch" where Aris Boch demands that Daniel Jackson treat his wound after capturing them: "I'm an archeologist" - "But you're also a doctor." - "... of Archeology."
- Stargate Atlantis had Carson Beckett do this in a couple of episodes:
- In "The Eye" he said: "I'm a bloody medical doctory, not a magician."
- In "The Brotherhood" the line is: "For the last time - I'm a doctor not a bloody fighter pilot."
- Lost had a character exclaim "I'm an internist, not an obstetrician" (which means, "I specialize in innards, not reproductive organs.")
- Bernard is a dentist, not Rambo.
Tom: Shephard says he's a spinal surgeon, not an anesthesiologist..
- In the Season 3 blooper reel, Elizabeth Mitchell responds to Matthew Fox's wondering how a flooded hatch can still function by saying, "Dammit, Jack, I'm a doctor, not a marine engineer!"
- 3rd Rock from the Sun had Officer Don say in one episode "I'm a cop, not a goat" when meeting Sally on a Hill at night.
- Moseby of The Suite Life On Deck wanted to put Zack on permanent detention for detonating a stink bomb in the chemistry lab. Tutweiler's response:
Tutweiler: I'm an educator, not a warden.
- Joked about in Criminal Minds.
Morgan: Can you do it?
Garcia: Remember on Star Trek, when Dr. McCoy always said, "I'm a doctor, not a miracle worker?"
Morgan: So you're saying you can't?
Garcia: No, I'm saying that I'm not a doctor.
- Played with in an episode of Friends where Rachel tells how her former fiancé, an orthodontist, once went to a Halloween party disguised as a dentist.
- The Smallville episode Rush has Clark say, "I'm an alien, not a cartoon!" when Chloe asks him if he can fly.
- An episode of Roundhouse referenced this by having Star Trek-esque scenes playing during a channel surfing montage. On the third appearance...
Kirk: Bones, this man is dying!
McCoy: Dangit Jim, I'm a doctor, not...oh.
- In the Big Bang Theory episode "The Desperation Emanation"
Sheldon: Leonard, I'm a physicist, not a hippie.
- On Friends, Joey has this line while pretending to be a doctor and unable to figure out a person's age from their date of birth.
Joey: Dammit, I'm a doctor, not a mathematician.
- In Final Fantasy VI, when Celes is asked to impersonate a famous opera singer: "I'm a general, not some opera floozy!"
- Another Celes line: "I'm a soldier, not some love-starved twit!"
- This line is said using "miracle-worker" in Final Fantasy IX. As seen in this screenshot.
- Knights of the Old Republic:
"Expletive: Damn it, Master, I am an assassination droid, not a dictionary!"
- In Dragon Age: Origins, when you ask Varick why he isn't going to be fighting in The Proving, he responds with "I'm a miner, not a warrior!".
- In Gex: Enter the Gecko: "Dammit Jim, I'm a doctor, not a pincushion!"
- In Mass Effect, when you encounter the Rachni, Shepard will ask Liara what they are (if she's on the squad at the moment). She will just say that she's an archaeologist, not a biologist, and is as clueless as Shepard.
- In StarCraft II, one of the medic quotes is "Dammit, I'm a medic, not a doctor! Oh."
- Technically speaking this is correct. Combat Medics don't need doctorates to be a medic but have nurse/orderly training instead.
- In Duke Nukem Forever, a dying Alien Queen blasts Duke so hard, he begins to lose consciousness. An EDF soldier comes to his help, but he turns out to be an engineer, not a doctor, and desperately calls for The Medic, as Duke blacks out. Of course, this being Duke, he gets better real soon.
- In Fallout: New Vegas, an NCR ranger hiding out in a bunker owned by the Brotherhood of Steel states in his journal that he is a scout, not an electrician, and that he can't quite get his radio to work.
- Even more directly, with the Wild Wasteland trait activated, NCR Ambassador Crocker will shout the line "I'm an ambassador, not a doctor!" in response to a question about Jet and the human heart.
- Durkon would like to point out he's a healer, not a foot stool.
- Likewise would Vaarsuvius like to state that (s)he is a wizard, not a divining rod.
- Likewise, Scout Arael cheerfully reminds you that she's a medic, not a messiah.
- In Schlock Mercenary, Tailor has to perform brain surgery on Tagon, which leads him to say, "I'm a clothier, not a doctor."
- In Wapsi Square, Monica is an Anthropologist, not a Psychiatrist. She even throws in a "Dammit Jin" for good measure.
- In Digger, Digger says that she's a wombat, not a lungfish.
- In the comments there's a Running Gag of "Dammit, Jim! I’m a x, not a x".
- The Ranma ½: The Abridged Chronicles version of Doctor Tofu can heal your wounds, unless they're costume-related.
Dr. Tofu: Ranma, I'm a doctor, not a tailor.
- In the Riff Trax of the 2009 Star Trek film, they come down on the usage of this for not being deep and raspy enough, asking to hear "those throat nodes and smoker's hack."
- Mr. Peabody, an Insufferable Genius Funny Animal in a Rocky and Bullwinkle short, used to constantly remind his pet human, Sherman that he was "A genius, not a miracle worker," (substitute sharpshooter, etc. to taste).
- Dr. Delbert Doppler from Treasure Planet says this as a Shout-Out to Star Trek: The Original Series.
- In the Adventures of Super Mario Bros. 3 episode "Oh Brother", King Koopa's pipes burst, leading to the following conversation:
Koopa: Well, don't just stand there, Kooky. Fix it!
Kooky: I'm a mad genius, not a plumber.
- A particularly brilliant example in Animaniacs when the Warner Siblings are backed into a corner in Hades:
Yakko: (William Shatner voice) Wakko...anything in your...Gag Bag that will help us..?
Wakko: Nothing, Yakko.
Dot: Nothing, Yakko.
Bones: Darn it, Yakko, I'm a doctor, not a magician!
- Roughnecks: Starship Troopers Chronicles, the animated series, has a conversation while defusing a bomb that goes something like this:
A OK, what color of wire do I cut?
B Why do ask me, I'm a doctor not a electrician!
A What's your favorite color?
A < cuts red >
B Why did you cut the red one? I said blue.
A You're a doctor, not an electrician.
- Ben 10 Alien Force episode "Paradox" with—who else—Paradox. After he managed to restore Kevin's age after he'd be
- Beavis and Butthead, similar to Saturday Night Live's example:
Captain Kirk: Bones, I've got an injured crewman here and you've got to do something! You've got to do something!
Dr. McCoy: Captain, there is a limit to what one man can do. Dammit Jim, I'm a doctor not a doc-... Oh, yeah, I'll get right on it.
Butt-head: Hey Beavis.
Butt-head: Those guys better look out for the Klingons near Uranus!
- The U.S. Acres episode "Swine Trek" from Garfield and Friends parodied this as well. When Orson Pig, playing The Kirk in a dream, asks Wade Duck, playing The McCoy, about a distress call that didn't sound right, Wade went, "How Should I Know?!? I'm a duck, not the Wichita Lineman!!"
- The finnish composer Jean Sibelius reportedly said "I'm a composer, not a psychic" when her wife wanted to know when he would be back from one of his drinking sprees.
- It was in Twenty Thousand Leagues Under the Sea.
- Wherein he did swear, but he wasn't talking to Kirk, so the complete memetic phrase still has yet to be uttered.