Exploited in his short story Unaccompanied Sonata, which is about a musical prodigy. He's turned down adaptations of it because it would be near impossible to write music as good as the story claims the prodigy's is. So it was an enormous honor when he changed his mind and approved Yaron Zilberman to adapt it because of his brilliant work in The Late Quartet.
Card: Here's a reason for making the character a musician — I don't have to create his oh-so-brilliant work. Even Ayn Rand, making Howard Roark an architect, had to describe his buildings, and alas, they are now very dated... With music, though, readers know that it can't really be recreated in fiction, merely referred to. But in a movie, the music has to exist. When I tell you in the story that people come from thousands of miles to hear Christian Haroldsen's nature-based synth music, or from dozens of miles to hear him improvise jazz on a honky-tonk piano, or learn his folksongs and are moved by them, you can believe it. In the movie, though, somebody has to compose that music, those songs; somebody has to perform it. And then you have to believe that people would respond that strongly to music that you have actually heard. If the music composed for the film is not utterly brilliant, will you believe the rest of the story? Will you care? Will the movie even work?
Averted in Ender’s Game and Ender's Shadow. Both Bean and Ender are shown to be legitimately smart through their actions during their education at the Battle School. Even then, some of their ideas are slightly-less-than-brilliant but are thus shown to be possible by any person; it's just that Ender figured them out faster than the other students. However, informing does occur during their fleet simulations at Eros, likely because it's near the end of the novel, and because tactics in space are too long and complicated to describe over and over.
In Heart of Darkness the enigmatic Kurtz is worshipped, feared, and adored by everyone who meets him. The characters have no lack of superlatives for his incredible genius and vision. Even Marlow, who feels contempt for his African cult, considers Kurtz a genius. The problem is that Kurtz himself barely appears in the story. By the time Marlow finds him he is weak and pathetic. About the only impressive thing Marlow does actually see is an amazing painting Kurtz made at one point.
In The Windup Girl by Paulo Bacigalupi, Doctor Chan informs the reader that Hok Seng is good and kind, yet throughout the book he is two-faced, lying, cheating, thieving, swindling, bigoted, manipulative, exploitative and generally psychopathic.
Thufir Hawat, from Dune, alleged Master of Assassins, fails repeatedly to thwart assassination attempts: 1: (Duke Leto Atreides' father) 2: (the assassination of Duke Leto's first born son because of a Harkonnen spy he allowed to sneak inside Caladan), 3: (not being able to stop Baron Vladimir Harkonnen from killing Duke Leto at the first Dune book), 4: (Rabban's hunter-seeker and its controller infiltrating Paul's room after having more than adequate opportunity to sweep the palace.). He also fails to goad Feyd into assassinating and supplanting good ole Uncle Vladimir. However, it is insinuated that Thufier is past his prime. He himself recognizes his failings and offers to resign at one point, only for Paul to point out that his training at least has been very successful.
Also, regarding Feyd-Rautha, Thufir had actually warned Vladimir about the assassin. He was playing them against each other.
Hawat also managed to overlook the fact that the Baron had poisoned him with a residual poison and was feeding him an antidote in his meals to ensure he couldn't survive more than a few days if he attempted escape. Hawat's failure to figure this out and obtain his own antidote supply eventually resulted in his own death.
Robert Langdon, of The Da Vinci Code and Angels and Demons, is supposedly a Harvard professor of "symbology" (the closest real-life discipline is semiotics, a subfield of linguistics and anthropology) and expert in religions. However, in Angels, he mistranslates "Novus Ordo Seclorum" as "New Secular Order", when any high school Latin student would know that it means "New Order of the Ages". This guy is supposed to be this huge expert on da Vinci, but he misses the simple "it's written backwards" code, which da Vinci famously used in all of his personal notes. As a supposed scholar of European history, his inability to read Latin, French, or Italian makes doing first-hand research difficult.
"HE is an expert in the works of Leonardo! SHE is a world-class cryptanalyst! IN A WORLD where the reader is presented with a facsimile of the document they're examining, it takes them several pages to deduce that they're looking at a page of mirror writing!"
His students are even worth taking as merely "informed". All the flashbacks of students he has in the classrooms seem to be of stock students who have questions and answers so naive that you wonder how on earth they could have possibly scored high enough to get into Harvard - or even get out of high school in the first place. Not to mention they are "informed" as having believed him when he told them early Judaism included sex rituals.
One of Magnus's powers includes "supernatural cunning", which he never demonstrates. He demonstrates knowledge, yes, but he is two thousand years old. In fact he walks into an ambush obliviously.
A scanner reveals that Iscarius Alchemy has an I.Q. of 666, and yet never demonstrates it.
Red Dragon has Will Graham who has been described by Crawford as having a special ability to relate to criminals like no one else, but all that's seen in the movie and novel is him doing basic police work. Finally averted in the series Hannibal, in which this process and its effects on Will are a major part of the story.
Similarly, Nicholae Carpathia's amazing oration is illustrated by a speech in which he rattles off a very long list of trivial details about the people in attendance and the agencies of the UN, and at one point reciting the names of all the member countries in alphabetical order. Actually listening to this speech would grow tedious very quickly, and also be a thorough waste of time.
The reader is told repeatedly that Alastor "Mad Eye" Moody is the most badass Auror to ever live, but in the two on-screen battles he fights, he's knocked out almost immediately in the first and outright killed in the second. Possibly justified by the fact that he doesn't appear in the books until after he retired; old age, paranoia and losing a leg have undoubtedly taken their toll.
To a lesser degree, Ginny Weasley (master of the unseen Bat Bogey Hex, which doesn't even sound all that formidable) also suffered this. Books 5 and 6 had Ron and Slughorn praising her for her powerful magic, but the reader never actually sees it in practice. It comes across as her own version of a Noodle Incident.
Played for Laughs with Dawlish. The first time you meet him, Dumbledore comments that he is an excellent Auror (got all O's on his exams!), but manages to knock him and his accomplices out. Later, he's the member of the team that fails to capture Hagrid. In the next book, Dumbledore tells Harry that he caught Dawlish spying on him, and knocked him out again. In the final book, he's sent after a little old lady and gets beat up again.Word of God implies that he is, in fact, a competent Auror, but simply has the misfortune of constantly beingOvershadowed by Awesome.
There was also what might have been Voldemort's signature move: Avada Kedavra, the Killing Curse. Supposedly, it's a lethal spell that has no countercurse or method of blocking it. Harry survived two direct hits from it, and Voldemort himself did the same once. The books do go a long way toward justifying these instances, however; sacrificing your own life to save someone from the curse is effective against it (which left Harry with no ill-effects other than his scar), and Voldemort survived due to his Horcruxes. (He wasn't as lucky as Harry. Though he survived, he became a barely-alive, ghost-like entity who required unicorn blood to survive.) The spell is also only a minor inconvenience to a phoenix; if it is used on one, it will just be reborn as if it had died any other way. It is even confirmed at one point that a simple solid non-magical barrier could block this spellnote This is of especial note, since Moody states in Goblet of Fire that the Killing Curse cannot be blocked. Though he might just have meant it can't be blocked magically., though it can do serious damage, like causing a desk to burst into flame, making it perhaps less menacing than it initially seemed, and no more different than evading gunfire.
Dumbledore is reported to hold the position of, essentially, the Head of the Supreme Court of magical Britain. Yet he never uses his authority to resolve any of the occurring cases when innocent people are being accused by the incredibly flawed wizardry judicial system. However, this may be a subversion, as Harry Potter and the Prisoner of Azkaban hints that the magical supreme court is corrupt. When Dumbledore does use his influence, he's immediately vilified by the other politicians and kicked out of office.
By the time of the Order of Phoenix there is no "maybe" corrupt anymore; Fudge manages to call a full criminal hearing, the type of which normally reserved for Death Eater-level murderers, for a simple case of under-age magic which at most carries a relatively minor sentence such as expulsion from Hogwarts. Related to the example above, Dumbledore does indeed use his knowledge of wizarding law to get Harry out of it, so it would appear his abilities are not quite as informed as they seemed before.
The Nimbus Two Thousand and One is introduced as superior to every other model of racing broom ever invented - up until the Firebolt in Book 3. According to Draco, it Outstrips the Nimbus Two Thousand by a considerable degree and completely wipes the floor with the Cleansweeps. So you would naturally assume that a whole team equipped with these fantastic brooms would be the equivalent of the Brazil soccer team going up against Samoa right? Well, no, actually. Though it is reported early on that the Slytherin team resembles a series of green blurs during their practice sessions, they never win the cup for the rest of the series, and we are never told of them ever having a scoreline against an opposing team that is ever anything more than completely average.
The books imply that while the brooms the Slytherin team uses are superb, the players themselves are not. Malfoy buys his way onto the team, they frequently resort to cheating, and it's mentioned time and again that the Slytherin team seems to prefer thuggish brutality to skill.
Speaking of Slytherin, even though the house supposedly values ambition and cunning, most of its members are Dumb Muscle. This is suggested to be thanks to in-universe Flanderization of the House's more extreme elements, as well as the fact that valuing a trait isn't necessarily the same as having a trait.
In Maximum Ride, Fang is supposed to be silent and expressionless. He's described as a "brick wall" multiple times. However, he is no less talkative than the other characters, and expresses emotion normally most of the time. In the few cases he doesn't, the narrator doesn't fail to point it out.
In Vampirates, Grace is constantly described as the smart twin, yet her brother figures out that she's on the ship with the eponymous creatures before she does even though he's never seen them.
Alistair MacLean's (actually John Denis) Air Force One Is Down goes to great detail describing master thief (now secret agent) Sabrina and how good she is, then portrays her as a classic Damsel in Distress throughout the rest of the book. Most notably in a scene where Sabrina can't lie to the Big Bad because she can't keep her thoughts off her face (and she's supposed to be a former criminal???)
Bella is also incapable of remembering even the smallest piece of information. For example, when Jacob tells her in New Moon that the vampires are dangerous and she should stay away from them, Bella goes into instant denial that vampires exist. She somehow fails to remember that Jacob was the one who told her the Quileute legend of "the Cold Ones" in the previous book.
Bella is said to be more mature than people her own age several times by several different people. Her mother even says that she was born middle-aged. This is the same girl who cries at the drop of a hat about nearly everything, is so hormone-driven that she practically jumps her boyfriend more than once (and after he's already told her that he wants to wait), wanders off alone in a place she doesn't know well when it's getting dark, is so attached to her boyfriend-of-less-than-a-year that she completely shuts down when he leaves her, routinely lies to her parents even when she doesn't have a good reason, spends an ungodly amount of time complaining about everything, plans a long car trip with a boy she barely knows who has treated her like crap since the day she met him (and lies to her father about it so if Edward tried anything he wouldn't know), strings along two boys because she "just can't choose," stomps her foot like a two-year-old when arguing with Jacob, etc.
To an extent, the Volturi. The characters go on about how ruthless they are and that they have no tolerance for lawbreakers. However, every time the Cullens do something that breaks the law, the Volturi always go very easy on them.
Bella's supposed to be a selfless, kind, caring, person who doesn't look down on others, yet she says that Jessica and her group are shallow, annoying, clingy and rude without much to back it up; she never does anything kind without ulterior motives, which rules out selfless; and she never seems to care that she is hurting people with her actions and lack of communication.
The eponymous protagonist of The Jackal Of Nar, Prince Richius Vantran, is a clear example of this trope. From being boldly described as "the best general of the Emperor of Nar" right on the book description, to having pretty much having the author attempt to have all signs pointing that the holder of that somewhat prestigious-sounding title(should be) is a badass, clever, war-savvy, fearsome character... only to have him actually showcase the maturity of a 13 years-old along with matching leadership capabilities, cringe-worthy emotional stability, not to mention how he also acts dumbly and boorishly , ditching his army in face of his men's doom to go whoring or blowing his disguise in ten different ways when he has to act stealthily... (to those that have read the book: note the adverbs, teehee) In any case, it goes well with the lackluster discovery that what sounded like a warfare-centric novel actually had whole kingdoms going at war and invading each other with armies totaling around fifty dudes...
Marguerite, in The Scarlet Pimpernel. Readers are told at length how "brilliant" she is, and she is repeatedly referred to as "the cleverest woman in Europe" by her peers. In practice, however, while she doesn't seem excessively dumb, her intelligence rarely seems more than average. She is consistently taken in by the Pimpernel's ploys, and the audience is almost certain to guess his identity before she does, even though she lives with him. This is probably partly a product of the portrayal of women at the time (even though the author was also female) and more importantly a product of the suspense narrative — since a lot of the drama would be lost if the narrator guessed things instantly. Regardless of the reasons, though, the descriptive passages tell that Marguerite has intellectual skills that she doesn't really demonstrate in the narrative.
Thrawn in the Star Wars Expanded Universe is a good example of why this happens. He's supposed to be a brilliant tactician, but most of those writing him aren't tactical experts, so they must either leave his abilities vague, show him outwitting the protagonist in nontactical ways, or give his opponents an Idiot Ball.
In Edgar Rice Burroughs's Thuvia, Maid of Mars, you hear Cathoris declaiming on his inventions, which are marvellous. He never shows any mechanical aptitude on stage, or even any interest in machinery.
In Hereticus, part of the Eisenhorn series, Glaw's daemonhost is supposed to be more powerful than Cherubael because of being less bound, but Cherubael kicks its ass anyway, later making some comment about being quite nasty. Possibly justified in that power does not equal intelligence - and Cherubael is very very clever. He might well have outsmarted Glaw's daemonhost. His track record in The Plan department is pretty impressive, what with engineering the events of the first two books as a way to free himself from Quixos.
Nearly every major character in Dostoevsky's Demons is obsessed, to one degree or another, with Nikolai Stavrogin. Each one has had some sort of profoundly moving experience with him—all of which took place, not only before the events of the novel, but even outside the country—and he exerts a lasting, though in most cases unintended and unpredictable, influence over each of them. Yet almost nothing he's seen to do justifies why they hold him in such regard.
Warcraft: In the book, Richard A. Knaak wastes no opportunity to remind everyone that Vereesa Windrunner is an expert marksman and a powerful hero in her own right... but her grand contributions to the plot of any book she appears in is to lose her bow in chapter 1, get kidnapped, fall in love with Knaak's Mary Sue pet hero, and getting married to Rhonin. Just like her husband, she goes from being an adventurer to suddenly leading the largest faction of high elves (mages in her husband's case) without any explanation at all.
The Girl with the Dragon Tattoo: Author Stieg Larsson repeatedly says that the hero Author Avatar Mikael Blomkvist is a wildly talented journalist and exceptional writer; the not-so-easily-impressed Lisbeth Salander is certainly taken with his prose, even before meeting him. This is generally a harmless case through most of the book, as Blomkvist shows real skill with public records and investigative techniques. However, the little bit of his prose seen is...not bad, exactly, but it's hardly very good.
Professor Moriarty is a huge example of this. Sherlock tells Watson (i.e. Doyle tells his readers) that Moriarty is the greatest criminal mastermind of all time, but you never get to see any masterminding. Furthermore, Holmes tells us about his cat and mouse game with the good Professor, but never shows or even explains either side of it, leaving everyone having to take his word for the brilliance on both sides. Add to that the fact that the vast majority of Holmes' mysteries were of a nature that no outside source could possibly care, be aware of, or benefit from, it makes Holmes' claims that Moriarty was behind nearly all the crimes he'd ever investigated look odd. He is a pretty paper thin archnemesis.
The (non-Doyle written) Seven Percent Solution takes this idea and runs with it, explaining that Moriarty is a perfectly harmless fellow (and Holmes' former math teacher), who Holmes merely perceives as a villain as a side effect of his cocaine addiction. In Michael Kurland's Murder by Gaslight, Moriarty is technically a criminal but generally benevolent, and inconvenienced by Holmes's paranoid fantasies.
In many adaptations Professor Moriarty has a stronger role — he is a classic Breakout Villain.
In the Babysitters Club books, the reader is informed in every book that Claudia is a fantastic artist. This is something of a Justified Trope, however, since it's very difficult to show that in a literary format. Interestingly enough, spinoff series California Diaries actually had Amelia's drawings in the titular diaries, by Stieg Retlin. They're at about the quality of, well, a moderately popular artist on tumblr today.
In the Sweet Valley High series, Elizabeth is said to be a brilliant writer and wants to become a journalist. Examples of her writing are almost never shown, and the few which do somehow make their way into the story are quite average.
In Robert E. Howard's "Queen of the Black Coast", Belit and Conan the Barbarian are said to form a Brains and Brawn — but all the brain seen from Belit is deciding to go somewhere, and Conan does most of the thinking that is done. Actually this is typical of most Conan stories by Howard and was most probably an intentional subversion of common pulp tropes: while strength, tenacity, and ferocity are what Conan (and, more generally, the Cimmerians) are famed for and what he builds his reputation on, most of his actual success stems from cunning, trickery, and quickly taking advantage of strokes of good luck. There is a running, sly implication in many of the novels that the whole "barbarian" thing presented to the reader is an intentional front to lead his enemies to expect savage assaults in daylight when what's coming is more like a knife in the dark.
There's one children's book that's called "Three Smart Pals", by Joanne Rocklin. It's about a trio of kids who are said to be very smart. On their way to an outing they see a shopkeeper that they know getting a sign ready. They "help" him make the sign "better" by taking out various phrases. Taking out a few words makes the sign funny, taking out every word but "Fish" makes the three mad because it's apparently implying that they're either blind or stupid. They finally make him make the sign blank, and call it "perfect!" When they come back, the guy hasn't sold anything due to his blank sign. Then they pretty much have him rewrite the sign exactly as it was before they got there, and suddenly it's a huge success. Wouldn't it have just turned out that way if they hadn't stopped to "help"?
The Voice of Freedom, prequel novel to the video game Homefront, presents a particularly blatant example of this trope. Ben, the novel's protagonist, is described throughout the novel as a smart reporter whose talents were wasted on celebrities and pop culture before the US was invaded by an implausibly reunified Korea, and then as an inspiring public speaker after the invasion, using his rousing patriotic speeches to raise morale among Americans and infuriate the Koreans. The problem is that he is a terrible writer (coincidentally, so are the novel's two co-authors) and his "rousing speeches" on the radio are vacuous crap. Seriously, one of them ends with him shouting "Hell yeah!" repeatedly. Um... yeah...
This Dorothy Parker quote comes from her review of a largely forgotten novel called Debonair by G. B. Stern. The title "debonair" supposedly refers to the "charming" lead character, whose debonair charm seems to consist solely of speaking in a cutesy accent
“I have yet to have an author inform me that a character is charming, and then, by that character’s deeds and conversation, convince me of that fact.” Dorothy Parker, "These Much Too Charming People"
As Parker continues:
"Debonair" may be her lover's word for her, but "God-awful" will ever be her nickname with me.
The Subterraneans are "hip without being slick, they are intelligent without being corny, they are intellectual as hell and know about Pound without being pretentious or talking too much about it, they are very quiet, they are very Christlike." So those are the Subterraneans. The only point in the summary with which I can agree is that they are hip; or, as Grandma used to say, hep.
Ivy, protagonist of The Magicians And Mrs Quent, is repeatedly said to be "quite intelligent", but she asks a lot of stupid questions, is slow on the uptake, and never does anything especially smart.
While the eponymous character of Septimus Heap is supposed to have amazing Magykal abilities, they do not quite show up anywhere.
Played as an important plot point in The Dresden Files series book Blood Rites, where Lord Raith, the patriarch of the White Court sex vampire clan, is supposed to be impossibly powerful due to the irresistible desire he arouses in his victims, whom he feeds on. This ability is never shown in the book, however, and through a series of clues Harry cottons onto the fact that Raith had his vampiric powers sealed decades ago by a curse.
An unusual example in Shogun. Toranaga is repeatedly stated to be a military genius and an amazing battle commander who has never lost a battle in his life, yet the reader never actually sees him leading in a battle, and the moments when he's seen planning a campaign are very brief and not particularly detailed (possibly because the author was not an expert on samurai warfare strategies). However, because there are many, many examples of his absolute brilliance in political chessmastery and manipulation, there's really no reason to doubt the people who say he's a great general, so he gets away with it better than most examples on this page.
Astrid Ellison is supposedly the smartest character in the entire series (earning her the title "Astrid the genius"), and while she isn't dumb and can quote various classical authors when the occasion demands it, some of her actions are painfully inept, illogical and can make you wonder whether she thinks at all. It seems to be that in the series, knowledge is not wisdom, and while Astrid is a genius in the former, she totally lacks the latter.
Lance is apparently absolutely perfect (according to Zil); well loved, talented, smart, handsome, strong, funny, kind hearted, modest...Book 4 protests when no one cares or even reacts to his death, even his current best friend, and his actions are proven to lack smarts nor kindness.
From LARP: The Battle for Verona: the entire US military. It's painfully obvious the author has only a rudimentary grasp of tactics and strategy, and what should have been a curbstomp battle never takes place for no good reason at all so that the main characters can go in and save the day instead.
In Firebird (Lackey), you only ever hear of Ilya's martial prowess; he never has to demonstrate it. Fortunately, he manages to win with skills he had ample time to demonstrate, avoiding abuse and acting more injured than he is.
Elistan in Dragonlance. It's told that he's great at motivating people and encouraging them, even able to convert Crysania from her skepticism to a fervent priestess of Paladine in one meeting. In practice, you're never actually shown any of this in any of his encounters with other people.
Anastasia Steele from Fifty Shades of Grey, being an Expy of Bella Swan easily falls under the trope. She's supposed to be a brilliant college student studying English Literature, but she doesn't have her own laptop or even an email address and Tess of the d'Urbervilles seems to be her only literary reference.
In The Wheel of Time, the villain Be'lal in the third book is supposed to be a brilliant Chessmaster, skilled general, and Master Swordsman. He only gets a chance to show off the latter before being killed off. Overlaps with We Hardly Knew Ye, as Be'lal gets built up impressively but only actually appears for a couple of pages. Of course, later in the series Demandred- who has pretty much the exact same quirks but is several times more Badass- is a very major villain, so the author may have just decided to do away with the redundant character early on.
Strangely retroactively enforced in Halo: Glasslands. The scientist Dr. Halsey was shown in previous fiction to be very smart, with many examples of her scientific knowledge (though admittedly with helpings of And Some Other Stuff, because it is future science, after all). However, Glasslands declares her to be not as smart as she's said to be, with Halsey herself reflecting that she had believed she was the smartest person alive simply because everyone else told her so. Its author reallydoesn't like Halsey.
Tsuruhara Iori spends almost all of War and Snowflakes carrying a duffel bag full of her kendo practice gear, but she does not utilize any swordfighting skills during the course of the novella.
The The Princess Diaries character Lilly is apparently a genius, which the insecure narrator constantly points out. However, her complete idiocy towards any even marginally social matter makes this difficult to believe. It's not even a case of Genius Ditz or Academic Alpha Bitch: she frequently resorts to childish bullying to achieve her goals, tells Mia nothing about a plan Lilly expects her to play a vital part in, and often attacks people for extremely petty reasons (condemning celebrities because they're physically attractive, cheats on her boyfriend in front of him, and believing it was somehow Mia's fault when Lilly's boyfriend used her for sex).
The Gladers from The Maze Runner Trilogy are picked for their intelligence from their childhood, though few of them actually show any real genius other than setting up a system of order in the Glade. The best real example is sort of roundabout, but Minho and Thomas coordinate battle tactics and formations on the fly during firefights despite never having used guns before. Otherwise, they're of average outlook and just above-average intelligence.
In L. Neil Smith's The Probability Broach and sequels, Griswolds security service (brrr!) is consistently said to be scary, with no evident grounds.
In Lee Correy's Manna, a very leading-edge company recruits the narrator, purportedly for his all-around competence. The thing he's most competent at is misunderstanding what's going on and thereby providing occasions for exposition.