Early episodes have the Ice King portrayed as a comedic Psychopathic Man Child with a lust for women (particularly princesses) much younger than him that was often Played for Laughs. Come the episode "Holly Jolly Secrets", which reveals that in a pre-apocalypse Earth, the Ice King was an intelligent, mild-mannered antiquarian named Simon Petrikov. After buying an ancient Scandinavian magic crown and putting it on as a joke in front of his fiancée (whom he affectionately referred to as "My Princess"), he did something he couldn't remember that drove her away forever. The Crown would begin seizing his mind and altering his body, giving him power over ice and snow. In the process, he heard voices and had constant visions that drove him utterly and completely mad until he became the Ice King we know today, unable to remember his past as Simon.
Made lighter by "Betty" where the actual reason his fiancee permanently left him is revealed to be him. More specifically, when the Ice Crown briefly has its powers and effects negated, a now lucid Simon is able to create a portal to the past in order to speak with her one last time. She chooses to jump into it rather than say goodbye.
Related to Ice King, "Princess Monster Wife" reveals all of the penguins are named "Gunther" or some variation of the name. "Evergreen" reveals why this is the case: The first person to wear the crown was a dinosaur named Gunther, who made a wish on the crown to become like his master Urgence Evergreen. As a result, the crown transformed him into a white-bearded ice wizard who could only say "Gunther, no!", an imitation of the man who constantly ordered him around. From then on, everyone else who wore the crown would have someone they would order around named Gunther.
In "I Remember You", it's revealed that the reason why Marceline has lived in so many different places is because Simon was her foster father during the mid-stages of his transformation into the Ice King. She keeps moving because he keeps instinctively looking for her despite being unable to remember their relationship, acting either pathetic or dangerous in manners that she couldn't bear. It also reveals that the reason she's so attached to Hambo is because Simon gave it to her.
In "Ocarina", it's revealed that the rare occasions that Jake's children have appeared over the previous season are in fact the only times he's ever spoken to them, because he's embarrassed that due to their Rapid Aging they're more emotionally mature than he is. At least one of them absolutely hates him as a result.
A minor one: In "Everything Stays", it is revealed that Finn, Susan Strong, and the various mutated humans living underground wear animal hats because in the years following the Mushroom War, wearing them was a method of camouflage and protection against vampires. Even after Marceline managed to kill all of them, the notion stuck for generations afterwards.
The original Adventure Time animated short that aired on Nickelodeon includes a scene where the protagonist Pen (later renamed "Finn") gets a pep talk from Abraham Lincoln, the King of Mars, which is played entirely for surreal humor. When the short film was spun off into a full-fledged TV show with a more consistent continuity, this detail was revisited, but treated much more dramatically: it turns out that Abraham Lincoln really is the King of Mars, and also that he's over 1,000 years old—and it's heavily implied that he made a bargain with Death for immortality after his supposed assassination, making him one of the few humans to survive the collapse of human civilization after the Mushroom War. This culminates in a surprisingly somber moment where he gives up his immortality to save Jake.
Anais rejecting Billy at the end of "The Egg" was played lightly, but "The Pest" shows Billy was actually deeply hurt by this and resorted to bullying Anais in an attempt to feel better.
Archer's fear of alligators. It was first introduced and Played for Laughs in "Pipeline Fever"; understandably, the other characters found it amusing that a reckless adrenaline junkie could be reduced to quivering fits by the mere mention of an animal. Two years later, "Once Bitten" revealed the origin of his phobia: he actually loved alligators as a child, but one of his last (and only) memories of his biological father was of him bringing him a stuffed toy alligator as a present. Archer apparently finds that memory so troubling that it takes a near-death flashback to bring it back.
Archer's constant abuse of his beleaguered manservant Woodhouse is also consistently Played for Laughs. But as we gradually get more details about Archer's childhood, we eventually learn that Woodhouse has cared for Archer since he was a baby, as he was Mallory's manservant before he moved into Archer's apartment. In fact, Woodhouse was far more loving and dependable than the callous and neglectful Mallory, and he's really the closest thing that Archer has to a father. With all of the abuse that Archer took from his mother as a child, there's the increasingly strong implication that he treats Woodhouse like garbage because he never learned how to show affection to his family.
Avatar: The Last Airbender: All throughout Season 1 and the beginning of Season 2, humorous things happen to Zuko that foil his attempts at catching Aang. At the end of "Bitter Work" (after being unable to create lightning), he's screaming into a storm about how cruel the universe has always been to him and finally breaks down. Suddenly, all those silly things go from the universe poking fun at an Ineffectual Sympathetic Villain to the turmoils of a young man desperate to go home and be loved by his father.
"The Beach" is a Cerebus Retcon for his sister, too. Azula fails in spectacular ways to socialize normally like other kids. However, the defection of Zuko and the betrayal of Mai and Ty Lee is a massive blow to her beliefs and philosophies she was trained into believing in despite the normal ways she "converses" through fear and manipulation which begins her Sanity Slippage into a Villainous Breakdown. Suddenly, you look back at this episode and realize that her inability to socialize messed her up far heavier than implied.
In the first season, Iroh states that he broke off his legendary six-hundred day siege of Ba Sing Se because he and his men were tired and homesick after so long at battle. At the time, it seemed to be just another indication of what a Lazy Bum he was, even back then, but in Season 2, we find the real reason he broke off the siege was because his son had been killed at the frontline.
Avatar Kuruk, during his brief appearance, claims that he lived in era of such peace that there was no need for an Avatar, leading him to being lazy and carefree. The novel The Shadow of Kyoshi, reveals this was a lie; Kuruk spent his entire life as the Avatar fighting to protect the world from an invasion of dark spirits, a deeply traumatic and damaging experience, and kept this a secret from the entire world leading to him developing his reputation as lazy and careless.
Beast Wars ends with the heroes victorious and returning home with Megatron strapped to the outside of their space ship in a humiliating fashion. And then comes Darker and EdgierBeast Machines where it's revealed that Megatron was able to escape mid-flight (which of course is made extremely easy when you're strapped to the outside of the ship and thus nobody inside is able to stop you) allowing him to conquer Cybertron before our heroes even arrived.
Big City Greens: The episode "Uncaged" begins with a Cold Open where Nancy liberates cows from a dairy factory only to get arrested. The episode "Chipocalypse Now" reveals she was doing that because the factory was threatening the family farm.
Early episodes show flashbacks to Bojack's childhood as being darkly humorous. This flips starting from Season 2, where the impact from his parents abuse and toxic marriage is shown.
Season 5 has a Running Gag where BoJack would forget he's in the Philbert's costume until someone makes him notice, "The Showstopper" reveals that BoJack's newly implemented painkillers addiction was starting to cause him to be incapable of distinguish between ''Philbert'' and his actual life, the other characters only realize of this after he almost strangles Gina on set.
Clone High: Mr. Butlertron's red sweater and catchphrase of calling people "Wesley" was just a continued Shout-Out to Mr. Belvedere, of whom Mr. B. is an Expy. Then the season two episode "For Your Consideration," as part of its "award bait" parody, gave Mr. B. a tragic backstory that explains why he does these things: Wesley was his human brother and childhood best friend, who Mr. B. abandoned when he learned he was a robot and not Wesley's biological twin. When Mr. B. returned home to an adult Wesley, the latter drowned in an attempt to help baptize Mr. B., leaving his red sweater as a memento.
Throughout Season 1 of Disenchantment we'd frequently see two sinister individuals watching Bean through a Crystal Ball and making references to some vague Evil Plan that obviously involved Bean. The seriousness of these scenes were usually undercut by the appearance of a servant named Jerry with a Simpleton Voice and marks on his head indicating some kind of brain surgery or lobotomy. Whenever he appeared they would either order him to do something, chastise him for being where he isn't meant to be or just speak to him rather condescendingly. In Season 2, it was revealed all three of them where Bean's mother, Dagmar's younger siblings. Jerry was the youngest and when he was a child, Dagmar put a crown with spikes on his head giving him Childhood Brain Damage, meaning every time we saw the three of them in Season 1 we were watching them abuse their brain-damaged younger brother.
in the first episode of DuckTales (2017) we were introduced to Scrooge's board of directors. To demonstrate how soul-crushing Scrooge finds working with them, they're portrayed as The Dividual, three Buzzards who are all voiced by Marc Evan Jackson and only one of which talks while the other two just repeat "No" over and over. As it turns out their leader Bradford Buzzard is the director of F.O.W.L. and the series ultimate Big Bad. The other two are just mindless clones who can literally only say "No", John D. Rockerduck calls them his "silent partners".
In the Earthworm Jim episode "Queen What's-Her-Name" we learn that Princess What's-Her-Name is called so because she was such The Unfavorite that no one bothered giving her a proper name at all.
Throughout the course of Ed, Edd n Eddy, Eddy was portrayed as a Small Name, Big Ego loud-mouthed scam artist who looks up to his brother and whose schemes usually go hilariously wrong and generally got his comeuppance at the end of the episode, often by being beaten up by one or several of the Cul de Sac kids. It's all Played for Laughs... and then the movie comes along, where it's revealed that Eddy's brother was a Big Brother Bully who regularly beat up Eddy, and his Small Name, Big Ego traits were the result of an Inferiority Superiority Complex he developed from this. His whole scamming and loud mouth nature were the result of trying to imitate his brother, whom he thought the other Cul de Sac kids respected — when in reality, they were all terrified of him. Knowing this, it makes a lot of the earlier episodes, especially the ones where Eddy suffers Disproportionate Retribution, very hard to watch.
In the Family Guy episode "Jerome Is the New Black", Quagmire tells Brian that Cheryl Tiegs was the love of his life who left him and the break-up is the reason why Quagmire is a sex addict. Three past episodes had clues that make the revelation logical (and not just something the writers pulled out of their butts): in "Emission Impossible," Quagmire has a poster of Cheryl Tiegs on his refrigerator (during the scene where Chris shows Quagmire the objects he found on the scavenger hunt); in "The Perfect Castaway," Quagmire's reason for why he'd choose to be blind (in a game the guys are playing) is because every woman he has sex with would, in his mind, be like Cheryl Tiegs; and in "Barely Legal" (the one where Meg becomes obsessed with Brian), Quagmire gives Meg the Shel Silverstein book The Missing Piece, telling her that he reads it whenever he feels that he needs to find the one thing in his life that's missing.
"Jerome is the New Black" also had a gag involving Quagmire's sister and her abusive boyfriend, which was played for tragic laughs (as Brian thought Quagmire's battered sister was just some one-night stand Quagmire had rough sex with). Two seasons later in "Screams of Silence: The Story of Brenda Q.", Quagmire's sister and her abusive boyfriend come back, and the abuse is Played for Drama.
In the episode "Yug Ylimaf" (the 200th episode where Stewie and Brian accidentally cause time to start going backwards), we see why the Greased-up Deaf Guy (a gag character who first appeared on the episode "The Thin White Line") is the way he is: he was walking beside a grease truck when it suddenly exploded, burning away his clothes and leaving him soaked in grease and deafened by the explosion.
Parodied in a Cutaway Gag from "Meg Stinks!" which shows how Peter funds all his wacky schemes: armed robbery!
"Where The Buggalo Roam" features a gag where Kif believes that kissing Amy is the same as making love to her. A later episode reveals that Kif's Bizarre Alien Biology causes his skin to become receptive to genetic material whenever he feels a great sense of love for someone else. In other words, kissing Amy really is making love to her.
The Does This Remind You of Anything? treatment of Bender's antenna turns out to be more literal than you'd expect. A male robot's antenna really is his reproductive instrument, since it's used to download a binary file to the female's drive which then creates a baby robot.
In a Season 1 episode, for a bit gag, Amy's parents set her up with Kif. In the Season 3 premiere, we learn that Kif has been hopelessly pining for Amy since then but has been too scared to ask her out again.
The first episode makes Fry's life in the year 2000 seem utterly miserable, so that it's understandable how he celebrates after being unfrozen a millennium later. Since then episodes have gone back and explored his previous life more closely, creating drama as Fry remembers his family, his girlfriend, and, most famously, his beloved dog.
Later, however, the trope is inverted, at least for his dog; thanks to time travel, a version of Fry eventually returns to the year 2000 and lives there until the end of the dog's life.
Mutants were shown to live in the sewers in one episode, and a Running Gag developed where they would stick their heads out of the ground to yell at people. The mutants' situation is Played for Drama later, when it's revealed that Leela is a mutant, whose parents gave her up so she could pass as an alien and live on the surface.
In "Teenage Mutant Leela's Hurdles", when the cast is de-aged to teenagers, teenage Amy is shown as fat and her father makes fun of her weight. In "The Prisoner of Benda," it's revealed that Amy was a compulsive over-eater, which is why she was fat as a kid.
Guy's grouchiness is shown to be justified every scene he's in. He's first introduced when he steps in a puddle and somehow sinks up to his waist. He's been trying to get his inventions onto the market for who-knows-how-long and on his most recent pitch, the device blows up in his face. Then his hat gets bent.
Sam's love of Green Eggs and Ham? It's his only memory of his mother, who made it for him once before putting him in an orphanage, and he's been eating it nonstop everywhere he goes in the hopes that he'll recognize the way she made it and reunite with her.
G.I. Joe: Resolute: In the original Sunbow cartoon, Cobra Commander was hammy, bumbling, and generally not meant to be taken seriously. Come Resolute he reveals this was all an act to encourage his underlings to act independently. He then takes charge and begins obliterating cities and executing his minions.
‘’Hero: 108'' Throughout the first season, Mighty Ray’s eyeballs detaching and the fact he hated eating the bananas that gave them the magic ability to shoot lightning was Played for Laughs. In season 2’s “The Eys of Moghty Ray”, it’s revealed that his original eyes were turned to stone by the Zebra Brothers, requiring that he receive a new pair from a Monkey god and his hatred of bananas was developed when he ate an excessive amount of them to try and eliminate Highroller, which caused him to suffer Power Incontinence.
Helga's family in Hey Arnold! is generally played for laughs: her dad is a pompous jerk who thinks everyone should bow down to him, her mom is a scatter-brained "smoothie" drinker, her older sister is an insecure perfectionist, and Helga herself acts like a bully because she's scared of expressing her true feelings towards people (namely her crush on Arnold). However, the episode "Helga on the Couch" episode is dedicated to her going to a therapist and airing her frustrations about her parents' neglectful behavior, as well as revealing that her crush on Arnold stems from him being one of the first people to ever be kind to her.
Kaeloo: In early episodes, Mr. Cat would have a Multiple-Choice Past, and some of the anecdotes he would recount would border on absurd. The show's fifth season reveals that due to the sheer amount of trauma that Mr. Cat has due to dealing with abuse in the past, he deliberately makes up ridiculous lies to avoid having to talk about what actually happened to him.
The Looney Tunes short, What's Up, Doc? has Bugs Bunny recounting his career to a reporter. He was a struggling young actor who was on skid row when show biz big shot Elmer Fudd offered him a part in his act. Unfortunately, Bugs's role was to play Butt-Monkey and get abused every time Elmer delivered the punchline. One night, Bugs takes things into his own hands and turns the tables on Elmer, finally getting laughs himself. Elmer, enraged at being upstaged, storms back onto the stage with a shotgun, fully prepared to murder his co-star in front of the crowd, who laugh, thinking it's All Part of the Show. Bugs, genuinely fearing for his life, nervously stutters, "What's up, doc?", raising a huge cheer, and he and Elmer realize they've found a hit, developing this into the hunting routine we all know.
In one episode of Mighty Max, it's Played for Laughs that Norman (the title character's centuries-old, badass bodyguard) is afraid of spiders. A later episode establishes the reason: he knows from a prophecy that he's destined to be killed by one.
Most of the third season of Moral Orel does this to the first season. The first season is a comedy and Orel's life is portrayed as a Hilariously Abusive Childhood. Despite Orel's parents being pretty bad people, Orel is quite cheerful for the first two seasons, which might have made the implications of this less noticeable. It's towards the end of the second season where Orel realizes his father isn't the awesome guy he thought he was. It might be a Cerebus Retcon for Orel himself as well.
The "Lost Commandments" in particular are given a specific explanation. At first just seeming like a general jab at Christianity, it turns out that the entire thing is a Puppington family tradition, going at least as far back as Clay's mother.
Supporting character Rose Lavillant, in the episode "Princess Fragrance", reveals that her crush on Prince Ali is at least partially due to his charity work for children's hospitals. "Guiltrip" reveals that Rose herself secretly suffers from an unidentified chronic illness, but keeps it secret out of a desire to not be pitied by her friends. After this is revealed, her perpetual upbeat demeanor looks more like a coping mechanism, and her admiration of Prince Ali's work becomes far more personal than it first seemed.
Over 4 Seasons, Marinette’s crush on Adrien led to her memorising his entire schedule, researching all of his habits and learning his full Overly Long Name. The Season 5 episode “Derison” reveals this is a Trauma Button reaction to her falling in love with Kim and then being victimised by a cruel prank since she was unaware he liked to pull them.
Monsters University hilariously implies that the Adominable Snowman was banished in Monsters Inc. merely for mail tampering. In Monsters at Work, it's revealed Abominable was actually banished for discovering a letter implicating Waternoose in the scream extractor plot, and Waternoose didn't want him spilling the beans to anyone.
Spike was often the Butt-Monkey of earlier seasons, with Season 3 having several entire episodes revolving around him hilariously failing at things. Starting with Season 4, Spike has a character arc revolving around his self-esteem issues and generally feeling useless.
In Season 2's "It's About Time", Cerberus leaves the gates of Tartarus, where many evil beings in Equestria are imprisoned. The whole thing is Played for Laughs when Fluttershy tames him like an oversized puppy, and is promptly forgotten after he's returned without a fuss. That is until the Season 4 finale, "Twilight's Kingdom, Part 1", where it's revealed that one of the prisoners managed to escape while Cerberus was gone, and happens to be the most catastrophic threat Equestria has ever faced.
The same episode also uses the overall concept of Time Travel as the setup of some wacky hijinks where Twilight drives herself nuts trying to decipher an incomplete message from her future self that turns out to be a pointer that she shouldn't drive herself nuts trying to decipher her message. The Season 5 finale "The CutieRe-Mark" revisits the same concept and explores just how catastrophically dangerous messing with the past can be in the hands of the unwise.
Early in the very first episode, Twilight rudely declines an invitation to an unseen friend's party to focus on her studies. It's treated as a quick Establishing Character Moment for her anti-social attitude, and is all but forgotten when Twilight moves away and makes new friends. Five seasons later in "Amending Fences", Spike reminds Twilight about this incident, spurring her to visit her hometown and try to reconnect with her forgotten friends. Only to find out the main friend in question — who already suffered from social anxiety and low self-esteem — had degenerated to become a bitter and lonely shut-in, because while she was on good terms with the others, she considered Twilight her Only Friend. It also serves as a reflection of the kind of pony Twilight could have become had she never made friends.
"Brotherhooves Social" provides an example of what kind of effect the Mane Six's absurd amount of series-wide accomplishments (which include saving Equestria on a semi-regular basis) would have on others. Here we see that Applejack is considered the family hero, but her older brother Big Macintosh feels somewhat resentful for getting ignored by their little sister Apple Bloom, who used to idolize him before Applejack started stealing his thunder. The fact that he rarely opens up to speak his mind suggests that he's been stewing over this longer than he'd care to admit.
For the first four seasons, Diamond Tiara is seen as little more than a one-note, sometimes laughable Spoiled Brat who picks on the Cutie Mark Crusaders in practically every scene she appears in. Come the Season 5 episode "Crusaders of the Lost Mark", it's made painfully clear that she gets it all from her mother's psychological abuse and desperately wants to change her ways, but feels trapped by her lack of self-identity and general sense of inadequacy compared to the free-spirited Crusaders.
Fan favorite Derpy Hooves initially became popular due to her Fish Eyes making her visually distinct from every other pony in the show. Her eyes and klutziness were used mainly for humor and cuteness... until a Meaningful Background Event in "Parental Glideance". In that episode, a flashback showing Rainbow Dash placing higher and higher in flying competitions also shows Derpy, who starts out at the top of the podium with normal eyes and performs progressively worse and worse as her eyes become more misaligned, strongly implying that she could've rivaled Rainbow Dash in flying ability if not for her eye problems. Adding to this is another flashback in "Where the Apple Lies" showing a slightly older Derpy in the hospital with bandages on her eyes, implying a failed attempt at fixing them.
Throughout Season 1, King's delusions of grandeur of being a powerful king of demons who was cursed into his current form are Played for Laughs, with him constantly demanding attention and attempting to get people to submit to him. Early on in Season 2, we see that he actually ties most of his identity to being the King of Demons, and learning that it was actually some vague childhood memories combined with stories Eda told him about kings leads him to a massive identity crisis where he can't tell what's real and what's fake anymore.
One of Luz's defining character traits is that she is downright obsessed with The Good Witch Azura, an in-series book and movie franchise that is entire basis of her Series Goal of becoming a witch. Throughout the show this is Played for Laughs, usually to make fun of the book's embarrassingly flowery writing and its annoyingly perfect protagonist. In Season 3, however, we learn the reason why Luz is so obsessed with these books is because she received the first book as a gift from her father shortly before he passed away, making her love of the series her way of preserving his memory.
The Real Ghostbusters: Janine's character design gradually changed throughout the seasons due to executive interference wanting her to have a softer appearance and personality, complete with changing her voice actor from Laura Summer to Kath Soucie. The sixth season episode "Janine, You've Changed," actually made this a plot point when the Ghostbusters and Slimer finally noticed Janine's new appearance by comparing photos of her. An analysis from Egon revealed Janine had literally been physically altered right down to her bone structure. The source of Janine's alteration was an evil spirit presenting itself as her Fairy Godmother granting her desire to be more beautiful so Egon would reciprocate her feelings. It was even explained in-universe that the reason no one noticed the changes was because the spell made them incapable of doing so but it didn't extend to recorded evidence caught on camera.
ReBoot: In "AndrAia'', Enzo being the only "Child" humanoid is explained to be the result of an accident involving his father's experiment destroying the city where Lost Angles is.
Rick and Morty: At the end of the episode introducing the Citadel, Morty asks what will happen to all the Mortys who lost their Ricks. He's told that the Rickless Mortys will return home and lead ordinary lives. Instead, "Tales from the Citadel" reveals that Rickless Mortys are kept away from their families and sent to a school where they are groomed to serve as docile replacements for other Ricks, with many shuffling through many Ricks. Mortys who fail to graduate are dumped in "Mortytown," a burnt out, crime infested section of the citadel where they victimize each other.
In the same show, Fred's status as a "Well Done, Son" Guy gets this treatment. In Season 1, his relationship with his emotionally distant father was Played for Laughs, through the obvious contrast between the relentlessly optimistic teenage nerd and his uptight politician father. But it gets a lot less funny after the first season's finale reveals that Fred Jones Sr. actually kidnapped an infant Fred Jr. from his real parents, and he has essentially been keeping him as a hostage for his entire life. Becomes more complicated when it's discovered that his birth parents, Brad and Judy were antagonistic, having become influenced by the Disk Pieces they were after. However, it is revealed that many of their positive qualities were repressed by the Greater-Scope Villain and it's revealed that the mayor really did care for Fred and he was, in a way, a better parent than his birth-parents (at least before the World-Healing Wave.)
In general, the classic Scooby-Doo formula that we all know and love — criminals pose as monsters to pull off overly complex schemes before being unmasked by the kids — has never really been questioned, and it's just an accepted convention that the Scooby-Doo universe is filled with crooks who all decide to pose as monsters for their own unrelated reasons. Mystery Incorporated's complex Myth Arc finally explores the phenomenon, revealing that it's not such a coincidence after all: all of the Gang's past adversaries have been the Unwitting Pawns of a malevolent Eldritch Abomination that compelled them to embrace their darker sides by taking the forms of monsters. On top of that, we learn that at least some of them (notably Fred Jones, Sr.) were inspired to adopt their monstrous alter-egos by dreams of real monsters from an alternate dimension.
Mystery Incorporated also humorously subverts this trope with its depiction of Blue Falcon and Dynomutt. The show's official explanation for Dynomutt's superpowers and enhanced intelligence is actually fairly dark: it turns out that he was nearly killed when he intervened to stop a break-in at Quest Labs, and he was given his robotic enhancements by Dr. Benton Quest in a last-ditch effort to save his life. The joke, though, is that Dynomutt is just as goofy and happy-go-lucky as ever, in spite of his past traumatic experiences; Blue Falcon, on the other hand, is a grumpy misanthrope with anger problems, essentially a tongue-in-cheek parody of Batman in Batman: The Dark Knight Returns.
The "Kenny Dies" episode, where he is Killed Off for Real... not in the usual over-the-top fashion, but slowly, due to a debilitating illness, with the episode's main plot revolving around his friends trying to get embryonic stem cell research legalized in the hope that a treatment can be developed before Kenny dies. The writers eventually brought him back anyway, after which he started dying very rarely. Many of the scenes in the episode are genuinely heartfelt and Played for Drama.
It's played absurdly straight in the "Coon and Friends" saga. Kenny, who is revealed to be the real Mysterion, has stated that his superpower is that he cannot die, and that even when he does die, no-one ever remembers it happening to him after he comes back (itself a bit of a retcon, since they sometimes did in the early seasons). He hates it so much that his near-Heroic Sacrifice at the end comes off like a desperate attempt to die for real. One might even see it as a Deconstruction of Negative Continuity. Also, this ability apparently comes from his parents having been involved with the Cult of Cthulhu.
In the episode "City Sushi", it's revealed Mr. Kim is an insane Caucasian psychiatrist with multiple personalities. By the end of the episode, everyone allows the Mr. Kim personality to take over completely, since curing him would cost the town its only Asian restaurant.
The two-part Wham Episode "You're Getting Old"/"Assburgers" reveals that all of Randy's wacky hijinks come from the fact that he's unhappy with his life and trying to find something that will fix the problem.
It might have always been there, but "Cash For Gold" revealed that Stan's grandpa has Alzheimer's disease, making him calling Stan "Billy" all those times a little less funny.
Meta-example that combines this and Real Life Writes the Plot: in the Season 10 episode "Manbearpig", the titular monster serves as an allegory for climate change, with Al Gore being depicted as a Cloudcuckoolander for believing in it. The next season, "The Imaginationland Trilogy" depicts Manbearpig as a very real Eldritch Abomination; and in the Season 22 two-parter "Time to get Cereal"/"Nobody Got Cereal," Manbearpig returns to South Park to collect its debt from a Deal with the Devil that even Satan himself cannot stop, depicting the climate change allegory as a more dire threat. Trey Parker and Matt Stone admitted that this decision was influenced by their own changing thoughts on climate change: in 2006, "Manbearpig" reflected the then-relatively mainstream view that the threat of climate change was heavily exaggerated (if not outright fabricated) by the American left—an attitude that mostly went out of fashion around the mid-2010s as it became increasingly clear that this wasn't the case.
In Star Trek: Lower Decks, Mariner is portrayed as a Military Maverick who does things her own was as a means to get around the red tape, keeping her as an Ensign. The series, early on, makes it clear something happened to make her like this, but it is never elaborated on. In the season 4 episode "The Inner Fight", it is revealed that she is a Shell-Shocked Veteran of the Dominion War and she acts out because she fears that if she were to be promoted, she would be forced to send her friends off to die.
Throughout the first season, we've seen Star battle monsters who have tried to steal her powerful wand, apparently for some evil goal. Come "Mewnipendence Day", we learn that Mewni's original settlers massacred the monsters and stole their land, while proclaiming themselves to be righteous. While Ludo himself is still treated as a joke, the desire of him (and later, the more threatening Toffee) is now re-framed from being Cartoonish Supervillainy to retribution.
The Running Gag of St. Olga's Reform School for Wayward Princesses, where Star is constantly being threatened to be sent there because of her hyperactive nature, and she reacts to the notion with comically exaggerated terror. When her fear turns out to be justified and the school is revealed to be an Assimilation Academy, the jokes come off as significantly less funny.
Queen Moon's overprotective nature is revealed to be from the fact that she became queen after her mother was killed and wasn't fully prepared to take up her mantle, so she wishes for her daughter to be prepared for such an unfortunate occurrence.
The depiction of Mina Loveberry as a strange and violent Cloudcuckoolander is later revealed to come from a mix of Super-Soldierserum giving her an unnaturally long lifespan and being the only remaining solider from those earliest wars against monsters giving her PTSD.
In the episode "Steven's Lion", when discussing whether Steven should be allowed to keep Lion, Garnet remarks that they "kept Amethyst", which causes Pearl to laugh hysterically at the joke while Amethyst glares at them in the background. Later that season, in "On the Run", it is revealed they did keep her after finding her abandoned in a Gem-creating facility known as the Kindergarten, and learning about her origins as a creature built for war (specifically to destroy Earth) gave her a deep sense of self-loathing that the others were unaware of.
In "Marble Madness", when Peridot meets Steven and wonders if "Stevens" have supplanted humans as the native species on Earth, Steven starts naming some of the other humans he knows and she silently records this information. In the Season 4 two-parter finale, "Are You My Dad/I Am My Mom", it turns out Homeworld interpreted this as a list of new types of human, and so send Aquamarine and Topaz to kidnap Steven's friends and neighbors to take to the Diamonds' People Zoo ahead of the planet's (believed) destruction.
The episode "Growing Pains" of Steven Universe: Future does this to every moment of dark comedy from the first season of the original show, with Steven realizing that everything from his first attempts at shapeshifting, to watching himself die due to time travel, to being kidnapped by Ronaldo traumatized him as much as his adventures with the Crystal Gems.
Over the course of Transformers: Robots in Disguise the Autobot Council is slow to react to threats facing Earth and respond the heroes requests for assistance. This is initially dismissed as bureaucratic sloth and the heroes manage to prevail on their own. Then Ratchet arrives from Cybertron and reveals that the Council is running a political smear campaign against Optimus Prime and those loyal to him. The series finale reveals that they were actually Decepticons in disguise and their inaction was a ploy to strengthen their grip on the populace before starting a campaign of galactic conquest, starting with Earth.
The phrase "Til all Are One" was originally created as a Transformers version of "May the Force Be with You" for The Transformers: The Movie said by the Autobots over course of the movie culminating in a New Era Speech marking the end of the war. In Transformers: Cyberverse, it has been taken up by Megatron and Starscream to allude to unifying Cybertron under their rule.
In The Venture Bros., how Master Billy Quizboy got his mechanical hand is told "Rashomon"-Style, and the end of the episode has him saying he doesn't really remember. A later episode shows that this was because he had his mind wiped. His arm was bitten off by a pit-bull, and was given the replacement which had a monitoring device so he could act as The Mole.
In the episode "The Battle Royale", The Black Cube of Darkness manages to get to the Ring of Power, but is unable to pick it up because of its lack of hands, and it leaves while a melodramatic sad tune plays. This is played purely for laughs, but a later episode, "The Black Cube" shows that this event caused The Black Cube to lose all respect as a villain and end up living in a seedy apartment, working a dead-end job as a fast food cashier, and being alternately mocked and feared by his neighbors.
The ending of "The Wanders" does this for Wander's entire philosophy. He doesn't just help because Good Feels Good, he helps because he knows what it's like to be helpless. It also implies that he hates that fact about himself, since he is very reluctant to merge with his helpless persona; without said persona, he's a daring and heroic individual who will stop at nothing to vanquish all evil beings, even Lord Hater.
