Prejudices are a funny thing; they can make those who have them delude themselves into believing they know strangers better than the strangers know themselves. Therefore, you sometimes see people in fiction ascribing certain qualities to other people, without having any grounds for doing so. Sometimes, they will even get angry or disappointed if the target does not or cannot live up to their baseless assumptions. If it's a Tsundere that held the image, expect her to hold the guy up to the standards anyway and yell at him if he falls out of line with her perceptions.
Subtrope of Psychological Projection. Related to In Love with Love, Loving a Shadow, and Replacement Goldfish. When a writer uses this unintentionally to describe their characters, it becomes an Informed Ability instead.
This is, of course, very much Truth in Television.
- In Lucky Star, Konata assumes a large foreigner is a violent kidnapper.
- In the Fullmetal Alchemist manga, May Chang hears about the eponymous Fullmetal Alchemist from various people, and forms a mental image of a tall, gentlemanly prince... and is horrified to find the short, rude reality. She later forms a similar image of Al's real body, after Alphonse, offended that she would think him similar to his brother, provides an exaggerated opinion of his own traits.
- Fullmetal Panic
- Kurtz Webber, who sees Kaname Chidori's picture, and then upon seeing the real thing assumes she must be an angel. That is, until Kaname chews her friend out for a horrible blind date and begins loudly yelling, causing Kurtz to become very disappointed.
- Gauron thinks Sousuke is a beautiful angel of death. Subverted in that Gauron was right to an extent, which Sousuke himself acknowledges later in the novels.
Sousuke: The only difference between him and me, is what is being enjoyed and what is not being enjoyed.
- Leonard Testarosa is definitely projecting a lot on Kaname, including forcing her to witness his traumatic memories, and drawing not-always-correct parallels between their lives. And he gets very pissed off when she finally makes it clear that she doesn't agree.
- Leo attempts something similar with his sister Tessa, but she knows him too well for it to work half as well.
- Kannagi: Crazy Shrine Maidens has several moments like this where the main character, Kannagi, will often berate Jin for not being her stereotypical vision of a loyal vassal who doesn't think for himself, just as the goddess expects of him. This often leads to powerful arguments between the two.
- Kirby: Right Back at Ya! has Fumu assume when this legendary Star Warrior Kirby steps out from his containment pod that it will be a tall prince with a slender demeanor and sword, only for it to reveal it is actually a pink puffball that can't even speak. This literally shatters her mental image.
- In Kurohime, the main character Zero has fallen in love with a powerful witch that saved him as a child, but as he grows older everyone tells him that the woman he fell for was an evil $^#%@, the problem is Zero refuses to listen. When Zero finally does meet Kurohime, she turns out to be a selfish brat who thinks men are toys and will use men to get whatever she wants and take over the world, going so far as even branding men with the kanji for "Dog" on their back. About a third of the way in the manga, though, she gets a lot better and actually falls for Zero.
- Naruto: A variation, where the wishful projection is on a person who is dead. A lot of Kakashi Hatake's baggage stems from his over-idealization of his deceased best friend, Obito Uchiha. Kakashi lost every single member of his original team in the span of a single year, and it broke him to almost beyond repair. Literally the only thing that kept him going was his promise to be Obito's eyes, so as a result, Kakashi devoted his entire life to being a memorial of his best friend. Every facet of his personality is modeled after what he believed Obito would have turned out had he managed to live to adulthood, and all his actions are in hopes to living up to all of Obito's ideals and wishes. Essentially, Kakashi is so hard on himself when it comes to his mistakes because he always believes that Obito would've succeeded where he failed (even though, realistically, that is very unlikely). In all his grief, he's forgotten that while Obito was a very kind and admirable person, he was still human, and far from perfect. Something that Kakashi only realizes when he learns what really happened to Obito.
- Comes up quite a bit in Batman; a lot of villains have trouble figuring out his identity because they all project parts of themselves onto him.
- Hugo Strange believes that Batman is living out a power fantasy since he's projecting his own lust for power on the hero.
- The Black Glove make a similar mistake, believing that Bruce is just playing a twisted game like they are. Both of them believe they know Batman better than he knows himself and both are off the mark.
- Zig-zagged with The Riddler, who will at times make perfectly reasonable (if still wrong) conclusions about Batman's identity (Batman's vast array of skills means he was formerly a soldier or special-operative) but also makes assumptions without any logical basis since he keeps projecting himself on him (Batman funds his crime-fighting by stealing money from the criminals he captures, which he also uses to bribe the GCPD).
- On a more general level, The Riddler tends to assume he's not only a lot smarter than he really is, but that his "lofty" intellect makes him more dangerous and feared than reality.
- Hush actually does know Batman's backstory and identity, but has trouble with understanding the impact it had on him. Since Tommy Elliot was a sociopath raised in an abusive household he utterly loathed the fact that Bruce Wayne got lucky by having his parents die from a mugger. In his mind, Bruce was then happily able to use his wealth and fortune to play ridiculous power fantasies free from parental control.
- Some interpretations of The Joker have him projecting his own nihilism on the entire human race.
- Naturally, Harley Quinn has this issue too, projecting the image of a loving and attentive spouse on The Joker. This is, of course, far, FAR from accurate, but the Joker is enough of a Manipulative Bastard to know that Harley is doing this and play it to his own advantage.
- Similarly, Lex Luthor seems to genuinely believe at times that Superman is a pompous, controlling alien who only wants the worship and slavish devotion of everyone on the planet...presumably because Luthor himself is an arrogant, controlling human who wants the worship of everyone on the planet. One story even has Lex rejecting a computer analysis that tells him Clark Kent is Superman, because he can't believe that any man would waste time being normal while having all of Supes' power at his disposal.
- In Encanto, Alma was the most vocal for the Arranged Marriage for Isabella and Mariano. It's noticed that out of the grandchildren, Isabella resembles a young Alma the closest and Mariano happens to look a lot like Alma's late husband Pedro. It's possible that Alma is projecting her desire to see the same love that she had with Pedro and for a married couple to live a a long life together that she and Pedro had been denied.
- MADtv had a sketch called The Average Asian, in which a completely ordinary fellow of stereotypically East Asian phenotype is expected to live up to all kinds of stereotypes. Eventually, one of them turns out to be true: he actually can summon a horde of ninjas to do his bidding, and he unleashes them to take revenge in one sketch when he finally has had enough of all the racist assumptions people make about him.
- In one episode of Law & Order: Special Victims Unit, Stabler admitted at the end that he failed to realize that a young woman was the killer because he saw her as a victim, not a person. In another he failed to recognize a husband going through a divorce was escalating and about to become violent because he was also going through a divorce at the time and wouldn't do that himself. SVU does this quite a bit due to their tendency to pull It's Personal cases more or less every week.
- In Poets of the Fall's Obsession Song "Carnival of Rust," the Love Hungry singer is depicted as Loving a Shadow from the outset, but it isn't enough that the object of his affection should love him back. He's also insistent they share the same dysfunctional, guilty level of fixation that he does, and telegraphs this via a loaded Trial Balloon Question.
D'you breathe the name of your saviour in your hour of need
N' taste the blame if the flavor should remind you of greed,
Of implication, insinuation and ill will, 'til you cannot lie still
- Quest In Show: Tristan Lambert is an outcast in his family. When he spots a black sheep standing apart from a flock of white sheep, he goes up to it and tries to comfort it with reassuring words.
- In The Importance of Being Earnest, the love interest Cecily imagines her guardian's rogue brother (not really his brother at all, but simply a friend masquerading as his brother, who does not realize that he is, in fact, his brother) as a bad boy from the stories she is told. When they actually meet, she says that she is already in love with him, and says yes to his marriage proposal that came during their introductory conversation.
- In Persona 4 Golden, the Hunger Social Link has Yu confronting Adachi alone after discovering his identity as the Serial Killer and trying to talk some sense into him. He then calls Yu an idiot and angrily asserts that the version of him Yu "believed in" was just a fictional representation of him living in his head, before telling him to stop wasting both their time and come back with the others to fight him.
- In Persona 5 Strikers, Akane Hasagawa is a lonely, angry girl who is a huge fan of the Phantom Thieves but projects her own romantic ideals on them. Namely, that her idea of justice is impulsive, selfish and destructive, differing greatly from the Thieves' idea of justice. She also mistook the Thieves' rebellion against specific, corrupted individuals as all authority figures, including her father, are inherently evil, all rebels are always good, hoping that the Thieves would dismantle the law enforcement she hated so much. So when the Thieves "betray" her by working with her father (who is a police officer), it shatters her trust in them and allows her to be easily manipulated by the Big Bad to turn on them.
- Yuki finds Piro's sketchbook, creates a fantasy about what he must be like, and then gets hostile when he fails to live up to it.
- Kimiko receives a railcard from Piro, creates a fantasy about what he must be like, and then gets hostile when he fails to live up to it.
- Erika receives unrequested assistance from Largo, creates a fantasy about what he must be like, and then gets hostile when he appears to live up to it.
- In Penny and Aggie, one unfortunate guy causes every girl who sees him to project their idea of a perfect guy on him. This inevitably leads to disappointment on both ends.
- She-Ra and the Princesses of Power: Shadow Weaver always favored Adora over the other Horde recruits she trained, calling her an "ambitious, cutthroat, ruthless warrior". But as Adora herself points out, she doesn't actually possess any of those traits and never did. Ironically, they better describe Adora's friend Catra—who Shadow Weaver blatantly despises.