In SpeculativeFiction, as in RealLife, technology is designed with certain [[IThoughtEveryoneCouldDoThat unquestioned assumptions]]: The user has the normal number of appendages, is within a certain generous range of sizes, can withstand so many G's of acceleration. The user can shoot lightning from her hands, or commune telepathically with computers... just like everyone else in the builder's species. But not everyone ''is'' a member of the builder's species, and that's where this trope comes in.

In certain settings, FinaglesLaw ensures these assumptions will cause disaster. Sure, sometimes it's a bonus, or even a built-in feature, that the alien saboteurs can't use the ArtifactOfDoom properly, but usually it's just a pain.

If a piece of technology only works for one ''specific'' user, that's LoyalPhlebotinum. This trope may involve PhlebotinumHandlingRequirements.

Sister trope to HumanFurnitureIsAPainInTheTail.


[[folder: Anime & Manga ]]
* ''Anime/{{Patlabor}}'': [[GentleGiant Hiromi]] is almost always seen in one of Section 2's trailers because he's simply too ''tall'' to operate one of their Labors. The one occasion we see him in one, his knees are up around his chest, preventing him from operating the controls.

[[folder: Comic Books ]]

* Since he's a robot with non-human fingers in a world without a capacitive stylus, ComicBook/AtomicRobo can't operate a touch screen at all. In one scene, he's actually seen complaining to Steve Jobs about how useless the [=iPad=] is to him. Later, when Robo has to answer a call on a smartphone, he literally can't, for the same reason.
* ''ComicBook/JudgeDredd'': The Judges' DNA-encoded Lawgiver cannot be used by anyone else. Unlike the 1995 movie however, they explode and ''can'' tell if a clone sibling is using it, since in the comics clone Judges are common.

[[folder: Comic Strips]]
* One ''Webcomic/{{Nodwick}}'' strip featured a villain who dedicated his time searching for a tunic that gave godlike power ... without learning that it was designed for a being with six tentacles and a very narrow waist.

[[folder:Films -- Animated]]
* In ''WesternAnimation/MonstersVsAliens'', the alien is octopus-like, and as a result his ship is controlled with what is essentially a DDR pad. Dr. Cockroach is still capable of using it though, albeit with some difficulty.
-->"Difficulty? My dear, [[spoiler: his Ph.D. is in ''dance''.]]"
* In ''WesternAnimation/ToyStory2'', Rex and Ham both have difficulty playing a video game because [[LivingToys they're so small]] their arms can't reach both sides of the SNES-style controller at once.

[[folder:Films -- Live-Action]]
* In ''Film/{{District 9}}'', alien weapons can only be used by those with the alien's arm, presumably due to some sort of DNA compatibility. [[spoiler: Then, of course, the protagonist ultimately gets an alien appendage and fires at will.]]
* In the movie ''Film/JudgeDredd'', the fact that a Judge's weapon can only be used by that particular Judge [[spoiler: or someone sharing that Judge's DNA]] becomes a plot point.
* ''Film/{{Dredd}}'''s Lawgiver is more like the source material's version. Kay attempts to use Anderson's Lawgiver [[spoiler: and gets [[AnArmAndALeg his arm]] [[StuffBlowingUp blown off]] for his trouble.]]
* In ''Film/TheAdventuresOfBuckarooBanzaiAcrossThe8thDimension'', Buckaroo gets confused at the climax when trying to fly the Red Lectroid Thermapod because its controls are, among other things, designed to be operated partially by the pilot's bare (and presumably prehensile) feet. He therefore has to turn control of the ship over to the Black Lectroid John Parker, who unfortunately "failed driving school."
* Subverted in ''Film/TotalRecall1990'', when Quaid activates the alien reactor. The activating mechanism is in the shape of a three-fingered alien hand, but Quaid just puts his fingers Spock-style and activates it anyway.
* Played with in ''Film/GalaxyQuest''. The Thermians are actually StarfishAliens, but the human characters can operate the ship because it's an accurate replica of the ship from [[AliensStealCable the TV show they were in]], which was of course operated by humans.

[[folder:Live-Action TV]]
* Occurs in ''Series/{{Farscape}}'' when anyone other than D'Argo tries to operate Lo'la. The ship requires D'Argo's DNA to function so it's...messy for someone else to use it.
* Stairs were impossible for [[Series/DoctorWho Daleks]] to use until they gained levitation technology. ''Series/{{QI}}'' speculates that ramps are a Dalek conspiracy.
* A lot of tech in ''Franchise/{{Stargate|Verse}}'' can only be operated by someone with the ATA (Ancient Technology Activation) gene. Luckily a procedure is developed that can give most people this trait, though those blessed by the plot are still inexplicably better at it.
** As well as some of the Goa'uld technology (e.g. hand devices) are only usable by someone who is or was a host for a Goa'uld (or Tok'ra) symbiote.
** Also, a lot of technology is created so that the Goa'uld ''can't'' use it. Whether or not they're problematic for Jaffa such as Teal'c or ex-hosts such as Carter varies.
* Became an issue for Creator/WarwickDavis when he appeared in one episode of ''Series/TopGear''. He has extensions so that he can operate the pedals of a car but he only has a set for an automatic (accelerator and brake, no clutch) and the "Reasonably Priced Car" is a manual. Richard Hammond's attempts to cludge together a work around were... less than optimal.


[[folder: Literature ]]

* In ''The Colors of Space'', by Creator/MarionZimmerBradley, humans need to be in stasis to use the FTL drive. [[spoiler:Or so the aliens who invented the drive claimed.]]
* Creator/MarionZimmerBradley's ''Literature/{{Darkover}}'' series:
** In ''The Heritage of Hastur'', the Sword of Hastur is protected by two force fields. Only a telepath can pass through the first one, but only a ''non''telepath can pass through the second one.
** Noted in ''The Forbidden Tower'': Terrans, who are usually right-handed, often have trouble using implements designed by/for Darkovans, who are usually left-handed.
* In one ''Literature/{{Animorphs}}'' book, our heroes steal a Bug fighter that is usually piloted by a Taxxon (a really, really big centipede with maybe six or eight arms), and is here piloted by an Andalite with two arms. Then they learn the ship was designed with a ''mutant'' Taxxon in mind, one with "twice the usual amount of appendages". They manage to fly it perfectly though.
** Ax actually says something like, "I now believe this ship was meant to be piloted by a Taxxon with twice the usual number of appendages." [[AlternativeCharacterInterpretation This may just be his way of complaining about having to pilot a ship meant to be piloted by a normal Taxxon.]]
** Considering the Yeerks are {{Puppeteer Parasite}}s, it's kind of surprising they don't have more equipment designed to be used by humans.
* In the Literature/LiadenUniverse, Val Con, a guy who's around 5'5, tries to operate a spaceship designed for a larger species of human. He gets seriously injured from this.
* One of the characters in Creator/HarryTurtledove's ''Literature/{{Worldwar}}'' books is Kassquit, a human woman raised by the alien, lizardlike Race. She must wear artificial "fingerclaws" to be able to use the Race's computers.
* The ''Literature/MyTeacherIsAnAlien'' series involves thousands of alien species living peacefully on one massive space station. This leads to some rather complex issues--for example, when the human protagonist first needs to use a bathroom he has to answer a series of rather personal questions to the computer, causing serious discomfort before he finds a toilet that will actually work for his anatomy.
* Similar to the situation in ''The Colors of Space'', the Tyr in C S Friedman's ''The Madness Season'' claim that FTL travel can only be performed by them because the method that they use causes a state of absolute terror for any other living thing in hyperspace. [[spoiler:It is later uncovered that there is more than one method of FTL travel, but the Tyr suppressed those in order to maintain control of the galaxy.]]
* In Anne Mason's ''The Stolen Law'', Vallusians have six fingers on each hand - two opposable thumbs. This leaves human protagonist Kira unable to work the gun they want her to train with, as its grip has two triggers that must be pulled simultaneously; more seriously, when an important piece of technology is sabotaged, it reveals the existence of a Vallusian traitor, as none of the other known races would have been capable of manipulating the necessary controls - she figures out how to hit the second thumbpad by laying one of her hands on top of the other, but that would have just made things more difficult, as there was only room for one ''arm'' in the closed space where the device was located.
** In the previous book, ''The Dancing Meteorite'', a Vallusian suggests helping the Arraveseans by piloting one of their ships, since it was originally a Vallusian model. Kira has to point out that the ship has been modified to suit the Arraveseans, who are less than five feet tall and have three arms and twelve hands.
* Averted in the novelization of ''Literature/TheLastStarfighter'', since the Gunstar is capable of detecting the species of its pilot and modifying its cockpit and controls to match.
* Franchise/StarWarsExpandedUniverse:
** In the ''ComicBook/XWingSeries'', Rogue Squadron's chief mechanic is a Verpine, an {{insectoid|Aliens}} race whose hat is engineering ability. Wedge has heard rumors of Verpine making modifications to the controls of starships that they see as improvements, without taking into consideration that most species don't think in base 8 or have microscopic vision. (Zraii is more careful than that.)
** The Givins' hat is mathematics. In one of the ''Literature/NewJediOrder'' books, Corran, Anakin, and Tahiri have some trouble starting a Givin-built starship until they figure out that the controls are arranged according to a bizarre math formula.
* In the Literature/ChanurNovels, Tully as the lone human in a ship crewed by a race of CatFolk aliens has to use a pick to operate the recessed controls usually operated by the Hani's retractable claws.
* The ''VideoGame/XBeyondTheFrontier'' {{novelization}} ''Farnham's Legend'' has a Teladi, a [[LizardFolk reptilian species]], have trouble with the computers on a wrecked Boron space station because they were designed for a species [[FishPeople with tentacles]].
* In the Creator/CordwainerSmith "Scanners" stories, only those who have been through the Haberman process (which basically involves blocking most of their sensory and some of their autonomic nerves; "Habermans" can see, but can't taste, smell, feel, or hear, and they have a mechanical control for their heart rate) can withstand the effects of the space drive; unmodified humans would go insane from what's known as the Great Pain and must make the trip while unconscious. Most of a ship's crew is composed of criminals sentenced to the Haberman process, supervised by a small number of volunteers who enjoy ''tremendous'' status and are allowed to occasionally use a technology that reverses the effects, turning their senses back on temporarily.
* A brief gag in ''Literature/LifeTheUniverseAndEverything'' says that Slartibartfast had been planning to spend his retirement learning the octraventral heebiephone, even though he knew perfectly well he didn't have enough mouths.

[[folder: Tabletop RPG ]]

* ''TabletopGame/CallOfCthulhu'' supplement ''Terror from the Stars''. The Mi-Go have a LightningGun which they fire by grasping it and altering its electrical resistance. Humans who want to fire it have to clip one of its wires.
* ''The Mechanoids'' from Palladium Books features telekinetic aliens. Their devices usually have the activation switches on the inside of the casing for a cleaner look. Human intruders who want to, say, use the elevator have to saw a hole and flip the switch manually.
* In ''TabletopGame/{{Exalted}}'' artifacts, manses, and demenses can, with a few exceptions allowing mortal use, be fully utilized by any essence wielder. Some have further restrictions on who can use them. For example, ''The Daiklave of Conquest'' can only be wielded by Dawn Caste Solars while ''The Hand of the Great Maker'' requires Chaos-Repelling Pattern (a Solar Charm) to attune and Wyld-Shaping Technique (another Solar Charm) plus either a five-dot Solar Hearthstone or a Protoshinmaic Vortex to be useful.
* The advent of metahumanity in ''TabletopGame/{{Shadowrun}}'' prompted product manufacturers to cater to dwarfs and trolls, who are very disproportionate to humans, elves, and orks. Most gear cannot be used as-is by dwarfs (who have shorter legs and bigger hands) and trolls (who are three meters tall with horns and ''enormous'' hands) and gear designed for them is unwieldy in others' hands. This contributes to racial prejudice; trolls regularly grow to be over ''eight feet tall'', meaning many of them need to ''crawl'' aboard a subway car. More humorously, there are dwarf communities where ceilings are only five feet high, meaning ''humans'' have to crawl through them.


[[folder: Video Games ]]

* ''Franchise/{{Halo}}'': The titular ringwords and many other examples of [[{{Precursors}} Forerunner]] technology can only be activated by [[spoiler:humans]] because they were designated by the Forerunners as their successors. Oftentimes, the alien Covenant have had to resort to kidnapping humans in order to attain access to Forerunner tech.
* Subverted in the end of ''VideoGame/MetroidZeroMission'' when [[spoiler:Samus escapes the exploding mother ship in a Space Pirate ship. The controls are glowing pads designed to be used by the pirate's claws, but Samus operates them just fine.]]
* Mentioned briefly in ''VideoGame/XCOMUFODefense'' with the Alien Grenades, which had some sort of weird psionically-activated arming mechanism that human engineers had to remove (with ''extreme'' care) and replace with a conventional timer. Alien firearms apparently have some sort of DNA scanner that locks out users not on the approved list, requiring a software hack to get around.


[[folder: Web Comics ]]

* Celia's ill-conceived magic artifact in ''Webcomic/TheOrderOfTheStick'' requires a jolt of electricity to activate. Not all humans can shoot magic out of their fingertips? How was she to ''know'' that? Humans don't even have an entry in the Monster Manual anymore! A particularly justified case, as Celia has very little contact with humans and regularly pals around with dryads, mermaids, fire spirits, etc. - she's used to ''racial'' abilities, and humans having such a wild array of abilities confuses the hell out of her.
** On the flipside, an attempt to hang Belkar fails because he doesn't weigh enough to pull the noose taut enough to snap his neck.
* A painless execution method, invented by a shapeshifting race in ''Webcomic/{{Starslip}}'', requires 21 appendages, so humans can't use it. Female humans, anyway.
* ''Webcomic/{{Subnormality}''}'s [[ Sphinx]] can't watch movies in modern formats.
** She can, as there are some tools that are used by people with little or no use of their fingers to pick up objects like [=CDs=] and [=DVDs=], and with keyboards, she can hold a chopstick in her paws. There are some quadriplegics who type that way.
* ''Webcomic/{{Freefall}}'' features a humanoid wolf with a wolf's snout, digitigrade legs, and black/white vision (Florence), a squid-thing wearing a humanoid environmental suit (Sam), a rotund robot of human-normal height (Helix), a giant construction robot (Sawtooth Rivergrinder), and assorted other semihumanoid robots (Dvorak, Tangent, and the robot tailor, for instance). [[ This]] [[ trope]] [[ shows]] [[ up]] [[ often.]]


[[folder: Real Life ]]

* [=CAPTCHAs=], those things where you have to prove that you're a human and not a bot by entering the text from an image, have quite a difficult time distinguishing between bots and blind humans-- because speech synthesizers and Braille displays can't render images. For this reason, an increasing number of CAPTCHA-protected sites include an option to have the characters spoken at you (which would benefit the hearing blind but not bots or the deaf-blind, though it's somewhat unlikely a person who is both deaf and blind would be operating a standard computer).
* A remarkable number of tools assume (often with dangerous consequences) that the user is right-handed.
** This includes nearly all bullpup firearms (magazine well behind the trigger), as attempting to fire them left-handed will fling red-hot cartridge cases into the user's face or down their collar. Many newer bullpup weapons can be adjusted for left-handed firing in the field, but heaven help you if you then pick up the wrong rifle by mistake, or a right-handed soldier picks up yours.
** Most firearms in general have safeties suited to right handed users. A leftie will either need to engage/disengage the safety in an awkward manner or use one with an ambidextrous safety.
** And let's not even talk about right-handed scissors, which left-handers have real issues using.
* RealLife {{Smart gun}}s, which is essentially a {{Defictionalization}} of [[ComicBook/JudgeDredd the Lawgiver]] (Well, without the [[StuffBlowingUp explosive charge]]). There are various methods, such as RFID chips, fingerprint scanners and magnetic rings that will prevent a weapon from firing if used by an unauthorised user. Their potential introduction has caused controversy among gun rights groups, who feel that they would not be reliable enough to stake their lives on.