{{Trope}}s are based upon very well-founded principles of storytelling. But, as [[SocietyMarchesOn society changes]], tropes may [[DiscreditedTrope fall out of favor]], either through association with [[ValuesDissonance something no longer considered acceptable]], or from simple overuse and falling into a cliché. At that point, [[DeadHorseTrope a subversion of the original may rise up to become the new standard]], and the original will be slowly [[ForgottenTrope forgotten]].

This is not a CyclicTrope; the original trope [[DeaderThanDisco probably isn't going to come back]], for one reason or another.

* Between the 1930s and the '60s, the U.S. government, in film, was portrayed as [[NobleProfession unequivocally good]]. The portrayal of corruption has become more and more common, though as PatrioticFervor rises, it may lapse back for a time. The late [[TheSixties Sixties]] saw ''liberal'' contempt for the U.S. government, but in [[TheSeventies the Seventies]] ''conservatives'' started to exhibit anti-government attitudes. There are currently antiestablishment factions on both ends of the spectrum (exemplified perfectly by the Tea Party and Occupy Wall Street), and they wax and wane in influence depending on the political alignment of whoever is in power at the time.
* Portrayal of Germans in Film:
** At first [[AllGermansAreNazis every German, from civilians to Gestapo, used to be]] [[AlwaysChaoticEvil monochromatically evil]] (This applied to UsefulNotes/WorldWarI, as well), with the concept of the [[TokenEnemyMinority "Good German"]] appearing as the conflict went on. Imperial-era Germans in fiction didn't even need anti-Semitism, racism or just plain world domination as a justification to be evil; they did terrible deeds [[ForTheEvulz just for the hell of it]].
** As [[RedScare Communists]] emerged as enemies and West Germany an ally in the real world, WWII movies redefined it to just Nazis being evil, most civilians became either resistance or misguided Nazi sympathizers.
** Further redefined in that Nazi-era German soldiers could be decent ''people'' and not just FacelessGoons[[note]]Members of the "Wehrmacht", the actual German military in that time period, need not even be Nazis in a political sense. Saying a German soldier is a Nazi is like saying an American soldier is a Republican or Democrat based purely on the party in power at the time.[[/note]]; but most SS and Gestapo still have souls blacker than night.
** More recently, a German might be portrayed as [[GermanicDepressives depressive]] or have [[GermanHumour odd senses of humour]]. The main constant though has been {{Oktoberfest}} and other related Bavarian traditions as lederhosen are almost always funny. Through it all, also, the eccentric Germanic professor or doctor has remained a comedy staple, even though plenty of other countries - some of them nowhere near Germany - now churn out brilliant scientists.
* Portrayal of scientists in Film:
** In ScienceIsBad movies, they were at best MrExposition. More often, they were the villain, a la the EvilutionaryBiologist.
** This slowly changed, from an unheroic mentor into an [[TheSmartGuy active part of The Hero's posse.]]
** This is more of a {{cyclic trope}} though -- a lot of pulp stories (and even earlier Victorian stuff) had a GeniusBruiser protagonist.
* Folk tales often portrayed wolves as [[SavageWolves evil, rapacious animals that preyed upon innocent livestock and humans]]. As the Industrial Age progressed, the wolves were no longer a threat, the people realized that wolves only kill to survive, and they're now portrayed as [[NobleWolf proud, majestic protectors of nature]] or [[PapaWolf just trying to feed their babies.]] The truth is somewhere in between (wolves aren't as saintly as they tend to be depicted these days, and they ''did'' kill livestock and, at least in Europe, the odd person)
** The same goes for many other wild animals. [[BearsAreBadNews Bears used to be considered so scary]] that people even [[SpeakOfTheDevil avoided saying their name.]] The word they used to use in place of their name was "bear." The fact that that word has now become the animal's actual name, and that we use it without fear, is a good demonstration of how much the trope has evolved. While bears still tend to be portrayed as ferocious, it's often justified by them being a MamaBear, and anyone trying to kill them is portrayed as the ''real'' villain.
* ''{{The Onion}}'' points out [[http://www.theonion.com/content/news_briefs/african_americans_go_from?utm_source=slate_rss_1 an example.]] African Americans were thought to be unable to compete at sports in before Jackie Robinson, now in the United States, it is assumed that African Americans are better at sports than others.
** Given the many stellar black athletes in the U.S. prior to 1947, it's probably more accurate to say that whites ''did'' know they could compete, but just didn't want to play alongside them.
* The Polish used to be the butt of many jokes ripping on their supposed lack of intelligence. However, once Polish-Americans settled in, they assimilated pretty well, even taking top-level positions in the US government - Zbigniew Brzezinski comes to mind. Recently, Polish-American and American Jews of Polish descent are often portrayed as smart - for instance Howard and Bernadette on TheBigBangTheory. This can result in UnfortunateImplications, since if you're of Polish descent and you ''just happen'' to be simple-minded, you'll get hell from everyone: bigots will mock you (and feel justified in doing so), and fellow Poles will [[UncleTomfoolery despise you]] [[StopBeingStereotypical for making them look bad]].
** This is not so likely in any recent portrait of Polish people in Western Europe shows. Since the European internal borders were opened, West European countries have seen a massive influx of Polish people seeking simple labour for relatively high wages. Since often they speak reasonable but [[StrangeSyntaxSpeaker not that well mastered]] English, lack higher education (since West needs more blue-collar jobs), they're again being mocked.
* It used to be that [[CatsAreMean cats were portrayed as evil]] in literature and society in Europe and later North America. For the most part they are portrayed more [[CatsAreMagic positively]] or neutrally now.
* Many students of mythology will tell you that depictions of the gods and goddesses in human stories underwent a complex metamorphosis over time: from freakishly inhuman beings, to anthropomorphized monsters who were needlessly cruel to humans, to despicable caricatures illustrating various vices, to bumbling yet lovable clown-figures, and finally to heroic beings who protected mankind from destruction. Some anthropologists attribute this gradual shift in attitudes to a parallel shift in how the Greeks and other ancient peoples regarded authority, social mores, and the universe itself.
* Computers were originally [[TheAestheticsOfTechnology depicted]] as [[BillionsOfButtons house-sized switchboards]] full of vacuum tubes. Later on, they began using transistors and sported [[ComputerEqualsTapeDrive reel-to-reel tapes spinning in the background]]. Still later, they used microchips, got much smaller, [[ComputerEqualsMonitor displayed their information on monitors]] and stored data on [[MagicFloppyDisk floppy disks]]. Right now, they're [[EverythingIsAnIpodInTheFuture small enough to fit in a pocket]] and stay [[EverythingIsOnline connected to the outside world]]. [[TechnologyMarchesOn Who knows]] [[{{Nanomachines}} what's next]]?
** There's a weird component to this, though: a savvy sci-fi producer will make their future supercomputer somewhere between the size of a washing machine and the size of a couple of refrigerators sitting next to each other, because that seems to be the sweet spot for how big supercomputers actually have been since at least the mid-1970s. Sure, you can put the compute power of a 1975 CRAY-1 in a smartphone now, but you can put ''many times'' that compute power in a refrigerator-sized cabinet ... and most supercomputing centers have the ''space'' for such a cabinet, so why not use it?
*** Also, with all the "computer farms" around nowadays, you can't say that some depictions of "modern" computers in some Sci-fi settings were not [[TruthInTelevision an excellent prediction]].
* Until TheNineties, a few small tattoos were enough to make a TattooedCrook. As small and medium-size tattoos went into mainstream fashion, the bad guys have started taking their tattoos UpToEleven, with KnuckleTattoos, facial tattoos and so on. Japan is an exception, as tattoos are still mainly worn by the {{Yakuza}}.
* CheatingWithTheMilkman derived from an era where houses regularly had milk delivered. Later on, when this was no longer true, the trope evolved into PizzaBoySpecialDelivery, which is based off of professions which do continue to make visits to customers' homes (besides food delivery, repairmen are also a common part of the joke).
* PhlebotinumDuJour is a good example of a trope which constantly changes as ScienceMarchesOn and the public become more familiar with a given technology or theory - as soon as one technology is widely understood (or discredited), speculative fiction turns to another, newer, sort to explain whatever technology is needed for the plot.
* At first a PornStash was a hidden cache of printed magazines. Then a hidden video/DVD collection. Then the contents of a computer's hard disk (and thumb drives, as they became more popular)[[note]]Or someone carefully hiding their [[TheInternetIsForPorn browsing history]].[[/note]].
* As ''WesternAnimaiton/MyLittlePonyFriendshipIsMagic'' changed the public's perception of ''Franchise/MyLittlePony'', the nature of MyLittlePhony would change with it. Whereas older examples of the trope would [[TakeThat mock]] the franchise, more modern ones would depict it in a more positive light, sometimes poking fun at its [[PeripheryDemographic older audience]].
* In high school settings, from the late 1990s onwards it has become very rare for the most popular girl in school to be portrayed as a BrainlessBeauty. Generally any AlphaBitch or LovableAlphaBitch who does seem ditzy will be ObfuscatingStupidity or at worst a GeniusDitz. Surprisingly the revelation that the pretty, bubbly girl is actually brainy is still usually treated as a stunning reveal in universe.
* As {{webcomics}} first began to appear as a medium, TwoGamersOnACouch became a good way for a strip centered around video game humor to frame its jokes. Thanks to SturgeonsLaw and [[SeenItAMillionTimes overuse]], it began to fall out of favor amongst web comic creators, but the concept of TwoGamersOnACouch survived through the world of LetsPlay, with ''WebVideo/TwoBestFriendsPlay'' and ''WebVideo/GameGrumps'' being among the most prominent examples.
* Quite apart from ScienceMarchesOn the ''narrative'' role of dinosaurs in films and television has changed over the years. Outside of comedy and cartoons (where friendly dinos can be found since [[WesternAnimation/GertieTheDinosaur Gertie's]] day) ReptilesAreAbhorrent was the overwhelming depiction for decades with even non-predatory dinosaurs being shown as ugly, lumbering monsters. ''Film/JurassicPark'' seems to have been the gamechanger where dinosaurs were as much a source of awe and delight as fear and even the T-Rex coming across as a dangerous but majestic beast more than a mere killing and eating machine.