My Little Pony: Paradise is well-versed in the tropes of fairy tales and legends, and yet she, a winged pony living in a Magical Land with unicorns and dragons, wonders why her life can't be more like a storybook. Uh...
The mane cast got a bit of Wrong Genre Savvy in "The Best Night Ever", in which all of them thought they were in fairy tales or various other stories. In reality, they were in a moral-drivenSlice of Life comedy, and this week's lessons turned out to be "Don't get your hopes up too high" and "good friends can help you make the most of a bad night".
Rainbow Dash forgot this again in "The Mysterious Mare-Do-Well" after her Acquired Situational Narcissism arrived, thinking she was the protagonist of a superhero story.
The villain Mane-Iac from Power Ponies knows that Humdrum is the Comic ReliefUselessSidekick to the titular characters and doesn't bother to incapacitate or capture him. Normally she'd be right, but this time around Humdrum is actually Spike who is farfromuseless. Surprise surprise, it bites her hard in the rear end.
Spike in the same episode, who makes the same assumptions about himself that the Mane-Iac does before he manages to realize otherwise.
One episode of Bonkers featured a Screwy Squirrel-type character who goes on a crime spree. At first Bonkers thinks he's unstoppable, because the character always wins in his cartoons. Then Bonkers comes to the realization that this is his cartoon, and so is able to defeat him.
In "Stanley's Cup" the characters correctly realize that they are in a typical sports movie and thus deduce that are bound to win against all odds. They also understand that to achieve that, they need to invite a really good player to their team for the final match, which they also do. In the end they turn out to be Wrong Genre Savvy and are beaten brutally. The opposing team was a professional hockey team and Stanley's team were pee-wee players about five years old. There was no other protagonist, just a parody of the cliched sports movie ending with what threatened to be a Shocking Swerve if it didn't cross the line twice. The pee-wee players are crushed brutally, deconstructing Underdogs Never Lose by showing pro players simply mauling tykes. After the underdogs do lose, the Littlest Cancer Patient dies from losing hope. It's Played for Laughs.
A three-parter has the gang playing as super heroes; however, when Cartman starts acting very villainous and the others try to call him out on it, he mistakenly believes he's still a superhero and it's the other boys who are the bad guys.
In the episode "Homer Goes to College", Homer is convinced that college is nonstop Wacky Fratboy Hijinx a la Animal House and Revenge of the Nerds, which includes believing Dean Peterson of Springfield University is a Dean Bitterman type and spends most of the episode pulling ill-conceived pranks on him, even going as far as to try to run him over with a car at one point. The irony is that Peterson is actually a good-natured younger guy who gets on well with the other students.
In "Brother From Another Series", Bart suspects that his archnemesis Sideshow Bob is up to no good when he's released from prison to work for his brother. While scouting around for clues, the following dialogue ensues:
Bart: He's more the same than ever. And I know where the evidence is. There's only one place where it could possibly be. Lisa: Bob's trailer at the construction site? Bart: (beat) That's even better! Let's go there. Lisa: What were you thinking? Bart:The haunted mine.
In "Grampa vs. Sexual Inadequacy" Bart becomes paranoid of bizarre conspiracies, believes the adults are spend most of their time indoors by day because of some hair brained conspiracy he cooks up. But the reason was they were into Grampa's special tonic which gets them really horny.
In an episode, SpongeBob becomes convinced that Mr. Krabs is a robot thanks to having seen a movie where robots take over the Earth (and some coincidentally odd behavior on Mr. Krabs' part). After he and Squidward have ruthlessly interrogated the "robot", Squidward thinks to ask SpongeBob how the movie ended, to which he replies that it turned out there weren't any robots after all; it was a misunderstanding. Oops.
Mr. Krabs in the episode "Born Again Krabs" thought that the Flying Dutchman's visit is All Just a Dream, turns out it's actually real. It also turns out that by screwing around like everything is a dream Krabs has driven the Krusty Krab into bankruptcy.
It seems Squidward is this way all the time: expecting things to turn out like they do in the real world, yet they constantly defy all logic.
In the first season of Martin Mystery, Diana would always think that the monsters were Scooby-Doo Hoax, when in fact they really were paranormal monsters/aliens.
In a few episodes of Teenage Mutant Ninja Turtles (2003), Michelangelo loves monster movies and panics when he meets creatures from beneath the earth, body-snatching aliens, or eldritch horrors. Someone always dies horribly. Lucky for him, he's not in a monster movie — he's in a Saturday Morning Cartoon.
Vincent Van Ghoul, having been in numerous horror movies and monster films, is aware of all the tropes and clichés associated with them, and panics when he's trapped in a house with a monster. So what's the problem with his understandable turmoil? He's in Scooby-Doo! Mystery Incorporated.
Wunschpunsch: In an attempt to prevent Bubonic and Tyrannia from casting the spell of the week in "Plant Panic", Maurizio placed some banana peels to make them trip and believed the plan would work because he'd seen it happening in cartoons. They simply walked normally and were oblivious to the banana peels despite having stepped on some. Maurizio later fell for his own trap. Just like it happens in some cartoons (and other media sometimes).
Transformers Prime episode "Thirst" has Starscream and Knockout confronted by a Terrorcon, and Knockout suggests shooting in the head based on seeing human horror films, citing tactics for killing zombies. As it turns out, he should have gone with tactics for killing vampires.
An In-Universe case happens in Drawn Together. Captain Hero spends much of the first episode thinking that the reality show he and the other housemates are on is one in which the contestants vote each other out and the last one standing receives a prize; as such, if Clara succeeds in ejecting Foxxy, he will be one step closer to victory. Foxxy tries, in vain, to convince him that it's not that kind of reality show.
In another episode, Hero is excited when he hears that Greeks are moving in next door, thinking the new neighbors are from a frat house. He tries to join in by wearing a toga at the house, but finds out that it's really a family from Greece.
In Rainbow Brite and the Star Stealer, Krys suffered under the delusion that he was the hero who would save the day, despite not having any powers and Rainbow Brite being way more badass than him. He eventually manages to save the day when he is given a powerful weapon and finally lets go of his pride to work together with Rainbow Brite.
In one episode of Jackie Chan Adventures, an evil cult called Magisters attempt to use Stonehenge as a magical weapon of mass destruction. After performing their rituals, they find the structure does absolutely nothing magical. They get carted off by the British Army too early to learn that Stonehenge is actually connected to aliens.