{{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, 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 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.
** 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.
* 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. 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. Due to wanting to prove all those idiots wrong, a lot of Polish people have become fiercely intellectual, resulting in them becoming one of the most intelligent ethnic groups around. This has actually started to seep back into media: Nowadays, you see someone in something who's Polish, they'll probably be a genius. 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.
* 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 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 what's next]]?
* 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]].