History Main / NecessaryWeasel

In copyright law in some countries, the doctrine of ''scènes à faire'' 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.

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 BadWritingIndex, an article listing some real (versus merely perceived) flaws.

* RubberBandAI: In various genres, but especially the RacingGame genre. Quite simply, if the player is able to trounce over the AI, the game gets boring.

* 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/{{Numbers}} 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?

%%* StockLightNovelHero: See [[Analysis/StockLightNovelHero the Analysis page]] for how the constraints of the genre have molded this trope.

* 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.

Can often be the cause of an EnforcedTrope. Some AcceptableBreaksFromReality are Necessary Weasels to particular genres as well. Contrast with the BadWritingIndex, an article listing some real (versus merely perceived) flaws.

* StockLightNovelHero: See [[Analysis/StockLightNovelHero the Analysis page]] for how the constraints of the genre have molded this trope.

* StupidEvil and TheBadGuyWins in dystopian literature, since 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.

* TheBadGuyWins in dystopian literature, since 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.

* {{Painfully Slow Projectile}}s and HitboxDissonance in BulletHell games -- otherwise they'd be impossible rather than just NintendoHard.

As a logical extension of TropesAreNotBad, 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.

* 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 it's stronger and/or smarter than a human.

* CleanPrettyChildbirth: In family friendly films. 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 often i required to be omitted to keep the rating.

* 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 it's stronger and/or smarter.

* CleanPrettyChildbirth: 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 may even be required to be omitted to keep the rating.

* 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 hard to justify just why a sapient creature would choose to be inslaved to someone else if it's stronger and/or smarter.

!!!Implausibilities:
* 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.

* StockLightNovelHero: See [[https://tvtropes.org/pmwiki/pmwiki.php/Analysis/StockLightNovelHero the Analysis page]] for how the constraints of the genre have molded this trope.

* Many Christmas stories involving SantaClaus do not address or adequately explain PlotHoles inherent in the premise, such as why no adults know he exists even though there are millions of toys showing up that nobody purchased, nor just how he manages to physically do that, and also why he has never been spotted by a passing plane or on radar.

* AdamSmithHatesYourGuts for [[IdleGame idle games.]] If the cost of things didn't scale, the game would quickly become completely trivial.

* Acting TooDumbToLive (even for a single thing, for one brief moment) on 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]].

* 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 some 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.