History Main / NecessaryWeasel

[[quoteright:240:[[VisualPun https://static.tvtropes.org/pmwiki/pub/images/weasel_55.jpg]]]]
[[caption-width-right:240:This is not a Necessary Weasel. It's a Gratuitous {{Weasel|Mascot}}, courtesy of the RuleOfCute.]]

->''"Be happy that weasels infest the world. Weasels are like motor oil for society. It wouldn't be fair to judge motor oil outside the context of an engine. If you put motor oil in your mouth, it would be filthy and slimy and leave a bad taste. But when that oil is inside an engine, it does an important job and you're glad it's there. Weasels are the same way. Slimy and disgusting, but essential."''
-->-- '''[[ComicStrip/{{Dilbert}} Scott Adams]]''', ''The Way of the Weasel''

As a logical extension of Administrivia/TropesAreTools, many tropes that might otherwise come across as gratuitous, offensive or just plain wrong in most genres are considered not just accepted in certain genres, but are practically a part of the genre. Complaining about the simple use of the tropes (as opposed to particularly offensive variations) in said genres is rather short-sighted and pointless, since, well, it's in almost ''every'' other work in the genre.

Can often be the cause of an EnforcedTrope. Some AcceptableBreaksFromReality are Necessary Weasels to particular genres as well. Also compare the AnthropicPrinciple, where certain factors, no matter how improbable, have to occur for the story to happen. Contrast with the WritingPitfallIndex, an article listing tropes that can lead to real (versus merely perceived) flaws. See also TropeEnjoymentLoophole, for when somebody's PetPeeveTrope is handled in a way that makes it no longer annoying (or vice versa).

A related concept is the doctrine of ''scènes à faire'' in some countries' copyright law. This doctrine denies copyright protection to elements that are considered necessary to a genre or setting. For example, a court of appeals in the United States has held that [[Film/FortApacheTheBronx a movie set in the South Bronx]] is expected to show certain features associated with the South Bronx at the time in which the movie is set and that showing such features is therefore not copyrightable expression.[[note]]Walker v. Time Life Films, Inc., 784 F.2d 44[[/note]]
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!!Artistic "flaws":
* RuleOfCool in general; "realistic" does not always equal "interesting."
* MoreDakka, StuffBlowingUp in summer action films.
* {{Invincible Hero}}es in combat-oriented {{video game}}s. [[NintendoHard Depending on the difficulty at least]] (or the player's skill).
* CleanPrettyChildbirth in family friendly films (and family friendly TV shows). Most people do not want to see body fluids and other gross things during a birth, particularly during scenes intended to be heartwarming, and it usually is required to be omitted to keep the rating.
* ToiletHumor in comedies featuring babies (see TheDiaperChange, ImprovisedDiaper, and TinkleInTheEye) or animals (see RoadApples, UrineTrouble, and ToiletDrinkingDogGag).
* An AudienceSurrogate character in a [[HaremGenre Harem]] anime.
* AnticlimaxBoss in WideOpenSandbox games. If a boss must be fought, and players can be optimized for something other than combat, then the boss must be beatable by the weakest character who can reach the fight.
* BossArenaIdiocy because they would be frustratingly hard or {{Unwinnable}} otherwise.
* PurpleIsTheNewBlack, and any other specific attributions of a particular colour to [[LightEmUp light]] or [[CastingAShadow darkness]] (like [[HeavenlyBlue blue]] or [[RedAndBlackAndEvilAllOver red]]).
* TheGodsMustBeLazy and similar tropes, like GodsHandsAreTied and HaveYouSeenMyGod in settings where vastly powerful deitie(s) exist. Such tropes preserve {{conflict}} by keeping the story from favoring the good side too much by making it too powerful, and allow for a [[MostWritersAreHuman human]] underdog hero to step in when the god(s) cannot or won't.
* JustHitHim: There would be no story if TheBrute simply punched a hole through the hero's chest, instead of dramatically tossing him around the room.
* WillTheyOrWontThey in stories involving the main character picking a LoveInterest. Unless there's something else to generate conflict, this trope will be used to keep the story from ending until TheyDo.
* CommonHollywoodSexTraits: Because ''real'' sex isn't always sexy, and a realistic depiction would likely go into IkeaErotica territory, most stories that feature sex or its aftermath are going to involve IdealizedSex. An exception is when the sex is played for [[VulgarHumour comedy]] instead of titillation.
* TheCoconutEffect: A sound effect, color, etc., that people expect to be there, such as horses' hooves that sound like coconuts being smacked together.
* Many Christmas stories involving SantaClaus do not address or adequately explain {{Plot Hole}}s inherent in the premise, such as why no adults know he exists even though there are millions of toys showing up that nobody purchased, among other [[HowCanSantaDeliverAllThoseToys questions]]. Attempting to answer these questions may diverge the story too far from the classic legend, and most people who like Christmas stories are willing to ignore these issues. Sometimes, the story does answer the questions, but these stories make it clear from the get-go that they're not your grandma's Christmas stories.
* RubberBandAI: In various genres, but especially the RacingGame genre. Quite simply, if you're able to do so well in a video game that the AI has no hope of beating you, the game gets boring. So sometimes, it's necessary to [[TheComputerIsACheatingBastard make the AI cheat a little bit]] to keep the game challenging.
* PlotArmor: In action or adventure stories, if no main characters ever put themselves in risky situations where their lives were on the line at least sometimes, the adventure and characters would probably be really ''boring'', but at least some of them also have to survive these situations even despite unlikely odds because otherwise they wouldn't be main characters and the story wouldn't be able to continue.
* StockLightNovelHero: See [[Analysis/StockLightNovelHero the Analysis page]] for how the constraints of the genre have molded this trope. Like an InvincibleHero in an action game, a man who just happens to have enough skills or luck to thrive to some degree when placed in an implausible situation is necessary, otherwise we would be reading about how a man gets torn apart by demons in thirty seconds [[ThisLoserIsYou and readers would really prefer to believe that they would be better than that]] if placed in a similar situation.
* HistoricalHeroUpgrade: If every real or mythological figure was portrayed as accurately as possible, the vast majority of these historical persons would be too morally repugnant for a modern audience to root for.
* {{Dramatization}}/VeryLooselyBasedOnATrueStory: RealLife is not like fiction. There are many boring parts, there's no real story arc, often many internal inconsistencies and details that are confusing for outside viewers, and as noted above, some "protagonists" may have done stuff that would make it difficult to root for them if it ''were'' a story while "antagonists" are rarely as black and white [[HistoricalVillainUpgrade as fiction tends to make them]]. Changing details for stories supposedly BasedOnATrueStory is required to make them fit into a cohesive and entertaining narrative (although contention can come from ''how much'' and ''what parts'' are changed from real-life events).
* {{Infodump}}: Sometimes, the audience will need to know something critical before it happens and, while usually a lot better to try and work it into the story gradually and over its course before it becomes relevant, there are some situations where it's just not possible without bloating and/or slowing the pace of the main plot to a crawl.
* MusicalWorldHypotheses: In some musicals, it makes sense that the characters are actually singing, while in others, it would make more sense if they were just imagining it.
* {{Fanservice}}: Such contexts as bathing (private or social), swimming, or exercising are a very good reason to show people off wearing little or nothing, and spiritual nudity is often considered another legitimate form especially in Japan. There is also debate on which instances of flesh exposure through clothing in general (usually female) come naturally to a given artist or are even justified, or are designed purely to titillate, although plenty of instances ''are'' clearly the latter; a lot of it has to do with actual focus.

!!Implausibilities:
* Plenty of Space Opera tropes:
** FasterThanLightTravel: Usually present in space-based ScienceFiction and virtually all SpaceOpera. Without it, you can't really go anywhere other than the Solar System, which, aside from Earth, is made up of some fairly unattractive real estate.
** AliensSpeakingEnglish or EternalEnglish, whenever the plot is not about learning to communicate with them. Sometimes hand-waved with a [[TranslatorMicrobes Universal Translator device]], but either way, the protagonists often need to communicate, and going back and forth with an interpreter is too clumsy to do all the time.
** ArtificialGravity, for "soft" ScienceFiction works (though otherwise "hard" film and especially television ScienceFiction will sometimes make use of it due to the extreme difficulty of producing true "zero-g" on camera).[[note]]Although, this may depend on how it's presented and achieved in-story. For example, just spinning the ship and having people walk on the side walls is perfectly reasonable.[[/note]]
** InertialDampening: Often accompanies FasterThanLightTravel (or at least any acceleration/deceleration that can be expressed as ".C"), needed to keep the crew from being rendered a fine paste in high-speed maneuvering or entering/exiting FTL travel.
** PlanetOfHats: Similar to AliensSpeakingEnglish, in stories where there is a lot of interplanetary travel, each planet is shown as having either only one culture, two cultures who are at war with each other, or, at most, three cultures consisting of two who are at war, and one who is below (like underground) or above (like super intelligent) it all. But if you just think about how many cultures there are on planet Earth, you see how unrealistic this is. But it's necessary, because otherwise it makes things too complex and confusing.
** HumanAliens[=/=]RubberForeheadAliens[=/=]HumanoidAliens: The likelihood of all or most sapient races across the universe being nearly or completely identical to humans anatomically is probably slim (especially since it's not like most animals on Earth look much like humans), but it sure is a lot easier on [[SerendipityWritesThePlot a limited budget and schedule]], and makes the non-human characters easier for the audience to visually empathize with.
** TwoDSpace specifically when used in pen and paper TabletopGame systems like ''TabletopGame/{{Traveller}}'', as it is difficult if not impossible to properly represent a three-dimensional map in a two-dimensional medium.
** FlashyTeleportation was used entirely to keep from having a DropShip sequence from eating [[Series/StarTrekTheOriginalSeries a certain show's]] entire budget, and were [[MisappliedPhlebotinum consequently poorly-implemented]]. The device as described completely breaks both conventional physics and quantum mechanics as we currently understand them over its knee, but there's no story (or, at least, more [[BottleEpisode cheapo episodes]]) if the shuttle animations budget guzzles up all the action sequences' money. Having the actors disappear and re-appear elsewhere in a cloud of sparkles is much cheaper.
* NoConservationOfEnergy in portrayals of superpowers.
* Ignoring of the SquareCubeLaw (as well as other laws of physics) in SuperHero, HumongousMecha, and AttackOfTheFiftyFootWhatever stories, as well as some types of StarfishAliens.
* InstantExpert in {{Role Playing Game}}s.
* BenevolentArchitecture - Sure, there is very slim chance that video game character's surroundings will be perfectly suited to that character's unique powers or abilities. Or that wreckage will form a path, rather than an obstacle. However, being realistic would mean {{Unwinnable}} or else easily passed.
* ThePerryMasonMethod: Because merely proving that your client is innocent is not enough for the audience;[[note]]or the general public, usually;[[/note]] they want to know who actually did it (and why).
* {{Painfully Slow Projectile}}s and HitboxDissonance in BulletHell games -- otherwise they'd be impossible rather than "just" NintendoHard.
* JumpPhysics in {{platform game}}s. Characters can often, at the very least, jump several times their own body height. Or they can leap or jump at angles that should be outright impossible given the real-world physics involved. Or you can [[DoubleJump jump after you've already jumped]]. But we wouldn't have a lot of video games if we didn't relax the rules around jumping a little bit.
* PowerCreepPowerSeep in {{Crossover}} {{Video Game}}s.
* The {{Masquerade}} in UrbanFantasy and other contemporary fiction with fantastic elements, allowing the writer to add such elements to the story while [[PlausibleDeniability keeping the setting relatable for the audience]].
* Similarly, ReedRichardsIsUseless is necessary to keep the larger setting of a superhero world from transforming into ScienceFiction with leotards.
* ContrivedCoincidence in {{farce}}. The more things that go humorously wrong, the better, so plausibility can go out the window.
* CellPhonesAreUseless in a ClosedCircle.
* ImprobablyFemaleCast in MagicalGirl shows.
* ImperialStormtrooperMarksmanshipAcademy in action stories; if the {{Mooks}} always hit their mark, the hero would be dead and the story would be over.
* MilitariesAreUseless in a ZombieApocalypse because otherwise it wouldn't be TheEndOfTheWorldAsWeKnowIt. Can sometimes be avoided however, if the story takes place early on or in a small area, allowing the military to save the day in the end ([[InferredHolocaust long term implications be damned]]); or the zombies are [[OurZombiesAreDifferent more powerful than usual]].
* OrcusOnHisThrone: Sure, it would be sensible for the BigBad to personally hunt down TheChosenOne. But then the protagonist would get splattered and there'd be no plot. Or the BigBad gets splattered too early and the plot is over.
* TheMainCharactersDoEverything because otherwise you'd have a massive cast fighting for what little spotlight there is. (And in the case of live-action, massively cost-prohibitive.)
* Acting TooDumbToLive (even for a single thing, for one brief moment) in horror stories. After all, even if DeathByGenreSavviness or [[DeathByPragmatism Pragmatism]] exists, many horror films depend on the heroes-slash-victims doing that one stupid thing that gets the ball rolling like [[DontGoIntoTheWoods going camping into the deep dark woods]] or visiting that friend on LovecraftCountry or [[CuriosityKilledTheCast getting curious about that weird thing they just noticed]].
* AllWomenAreLustful or AllWomenArePrudes: Guess which one of these two opposite tropes is enforced in the porn genre. You have a 1:1 chance.
* YouCantThwartStageOne because even if by all rights they should have be able to, doing so would usually make the entire rest of the story [[{{Padding}} irrelevant to the now resolved plot]].
* AdamSmithHatesYourGuts for [[IdleGame idle games]], thanks to DiminishingReturnsForBalance. If the cost of things didn't scale, the game would quickly become completely trivial.
* PlotLeveling in a PostScriptSeason. It's hard to scale the plot down from the former GrandFinale without losing viewer interest. This has to be done carefully, though; if things scale up too much, the show will start looking like a self-parody.
* StupidEvil and TheBadGuyWins in dystopian literature: Even if [[DystopiaIsHard it's implausible they rise and hold onto power]], the whole point of the genre is to raise awareness of the horrors of dictatorship so that the audience doesn't let it happen here.
* ThePowerOfLove (or its more vulgar cousin, ThePowerOfLust) being some kind of incredibly awesome force in stories that label themselves as (even partially) romances. Because if you're gonna write a 500-page tale about TheEveryman going against absurdly long odds for the sake of some girl and succeed, it's obvious there's got to be some kind of equalizer.
* HappinessInSlavery in the {{Mons}} genre. All {{Mon}}s typically serve humans because this is a cornerstone of the genre. There may be some attempt at an explanation or handwave, but they inevitably fall short because it's very hard to justify just why entire races of sapient creatures would willing choose to obey someone else, especially if they're stronger and/or smarter than a human.
* KeystoneArmy or NoOntologicalInertia: Following an epic FinalBattle with the HiveQueen or MonsterLord with the protagonists gradually sweeping up their remaining forces would end up being really tedious, unimportant to the plot, and disinteresting to the audience. Having all the {{Mooks}} [[DecapitatedArmy give up]], [[WorldHealingWave disappear]], or [[InstantWinCondition die]] right after the BigBad is defeated wraps things up neatly without ruining the pacing at the end, even if the idea that an army would immediately crumple with their leader dead is rather illogical and overly convenient.
* ArkhamsRazor in a series with TheExoticDetective: because if the whole idea of writing about [[Series/{{Monk}} a man with absurd amounts of OCD]] or [[Series/{{Numb3rs}} a highly-reknowned mathematician]] is that they have some kind of insight in a crime that a regular police detective doesn't, and this insight is instantly disbelieved (or worse yet, is wrong) then why write about someone using an "exotic" method to solve a crime?
* A DarkSecret or two is possible in any story, but in a Mystery, almost every suspect (the characters with most of the stage time) has one.
* DownToTheLastPlay is far more frequent (proportionally) in sports dramas than in real life, but a climax wouldn't be properly dramatic without it.
* TeleportersVisualizationClause is nearly always used with video game WarpWhistle systems in order to prevent SequenceBreaking from causing gameplay bugs.
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A related concept is the doctrine of ''scènes à faire'' in some countries' copyright law. This doctrine denies copyright protection to elements that are considered necessary to a genre or setting. For example, a court of appeals in the United States has held that [[Film/FortApacheTheBronx a movie set in the South Bronx]] is expected to show certain features associated with the South Bronx at the time in which the movie is set and that showing such features is therefore not copyrightable expression.

** TransportersAndTeleporters were cooked up entirely to keep from having a DropShip sequence from eating [[Series/StarTrekTheOriginalSeries a certain show's]] entire budget, and were [[MisappliedPhlebotinum consequently poorly-implemented.]] The device as described completely breaks both conventional physics and quantum mechanics as we currently understand them over its knee, but there's no story (or, at least, more [[BottleEpisode cheapo episodes]]) if the shuttle animations budget guzzles up all the action sequences' money. Having the actors disappear and re-appear elsewhere in a cloud of sparkles is much cheaper.

* {{Fanservice}}: Such contexts as bathing (private or social), swimming, or exercising are a very good reason to show people off wearing little or nothing, and spiritual nudity is often considered another legitimate form especially in Japan. There is also debate on what types of flesh exposure through clothing in general (usually female) come naturally to a given artist or are even justified, or are designed purely to titillate, although plenty of instances ''are'' clearly the latter; a lot of it has to do with actual focus.

* {{Fanservice}}: Such contexts as bathing (private or communal), swimming, or exercising are a very good reason to show people off wearing little or nothing, and spiritual nudity is often considered another legitimate form especially in Japan. There is also debate on what types of flesh exposure through clothing in general (usually female) come naturally to a given artist or are even justified, or are designed purely to titillate, although plenty of instances ''are'' clearly the latter; a lot of it has to do with actual focus.

* {{Fanservice}}: Such contexts as bathing, swimming, or exercising are a very good reason to show people off wearing little or nothing, and spiritual nudity is often considered another legitimate form especially in Japan. There is also debate on what types of flesh exposure through clothing in general (usually female) come naturally to a given artist or are even justified, or are designed purely to titillate, although plenty of instances ''are'' clearly the latter; a lot of it has to do with actual focus.