A Know-Nothing Know-It-All is a character who insists he or she knows everything; is always right; that they were the actual original creator of an idea; and who generally has an extremely high opinion of themselves and their abilities.
Nothing could be farther from the truth. They are grossly misinformed, or just lying, about everything they talk about with authority. They create nothing new, and are Ignorant of Their Own Ignorance. Their abilities could best be described as "scarce". Such people are, in fact, the living definition of the word charlatan.
While many characters show signs of being this, very few have it as a major facet of their character. For example, Peter Griffin of Family Guy tends to spew horribly misinformed information, but oddly enough, sometimes he's right, in the rather odd world the series is set in.
Little Known Facts are occasionally in the Know-Nothing's mental arsenal, thanks to their obtuse quality, but naturally, the research won't be. Hopefully, they're at least Entertainingly Wrong.
A Real Life engine driving this is the Dunning-Kruger effect, where the less competent are paradoxically more likely to consider themselves good at a task (because they are equally incompetent at assessing their own performance at it).
Can sometimes intersect with the Jerkass. Compare Feigning Intelligence. Contrast Insufferable Genius, who has the same arrogant attitude but is not incompetent. Actually listening to one may result in The Blind Leading The Blind. Compare Small Name, Big Ego, who both want to be recognized and appreciated, but take different paths to it. For a more "physical" version, see Boisterous Weakling.
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Autor from Princess Tutu fits this trope to a T...at least at first. He's an insufferable know-it-all who believes that he's a descendant of Drosselmeyer and also the absolute expert on the subject of his powers. He puts another character who wants to learn about his powers through a series of ridiculous 'training' exercises, including standing in the middle of a room for three days without eating or sleeping and only using "blue and black ink in a seven-to-three ratio". Eventually he's humiliated when the character he's training proves to have much more power than him...if he ever had any power at all. In the end it's slightly subverted, however—the character he "trained" is forced to go back to him for help because he actually is one of the best experts on Drosselmeyer.
In Axis Powers Hetalia, South Korea always claims he invented everything (well, almost everything. No one takes responsibility for condoms).
Takashi Yamazaki from Cardcaptor Sakura is always making up lies he claims to be facts. Interestingly enough, while most know he's lying, both Sakura and Syaoran both tend to believe him at first, before Chiharu breaks it to them that they're being lied to and lays the smackdown on Yamazaki.
Sakuragi Hanamichi from Slam Dunk is actually pretty stupid but always goes around saying "Ore wa tensai!" (I am a genius) and "Ore wa tensai baskettoman!" (I am a genius basketball man)
One episode of Lupin III Red Jacket featured Sherlock Holmes III among a group of detectives hired to outsmart Lupin. In the original version, he was a cultured gentleman. The Geneon Gag Dub turned him into a total nitwit who is always either stating the obvious or completely ignorant of the obvious — for instance, upon noticing an opulent dining fork, he proclaims it "a dining implement of some kind; a bit showy, whatever it is." Granted, the Holmes seen for most of the episode is actually Lupin in disguise, and when the man himself gets a chance to talk he seems pretty on the ball.
Saori Takebe in Girls und Panzer tells the girls on their Tankery team all about how to win over a guy. Then one of them innocently asks if she has a boyfriend, to which she becomes speechless, since she never had one in the first place. The girls try to cheer her up anyway.
Sakura Haruno is a practical Deconstruction of this trope from Naruto. While she was one of the top students of the Academy (second only to Ino who had became the Kunoichi of the Year), she considered herself a lot stronger than the 'Dead-Last' Naruto Uzumaki since she equated 'knowing more about textbook things translates to real life'. During her first real mission to Wave, she realized Naruto was not only stronger than her but had pulled far ahead and during the Chunin Exams, she sacrificed the long hair she had grown meticulously so Sasuke would notice her in an attempt to save her teammates who were unconscious from the battle with Orochimaru. Sakura eventually becomes Tsunade's apprentice, Takes A Level Of Badass several times and during the last stage of the War Arc she can keep up with KCM Naruto and a Complete Susano'o EMS Sasuke.
Jack Chick. Beyond his tin foil hat theories about the Jesuits founding communism as part of a centuries-long plot to get Russian gold, he even manages to get very basic facts wrong. Like claiming that Kaiser Wilhelm II was Catholic. Wilhelm and his ancestors had been Protestant - first Lutherans, then Calvinists, then Altpreussische Union (an amalgamation of the two) - for ca. 400 years.
Scuttle the seagull from Disney's The Little Mermaid. He claims that a fork is a thing for styling hair, a (smoking) pipe is a musical instrument, and also uses a telescope backwards.
This gets Lampshaded later on in the film when he's trying to warn Sebastian about something. Sebastian is understandably skeptical, and Scuttle shouts "Have I ever been wrong? I mean, when it's important?"
Friend Owl from the Disney's Bambi. The 'advice' he gives Bambi and his friends is actually terrible advice to give to young animals. Fortunately, it mostly gets ignored once "twitterpation" sets in.
Jasper in 101 Dalmatians. His shtick with Horace is that Horace hits upon what's really going on and then Jasper emphatically calls him an idiot for getting such a stupid idea.
Mr. Thicknose in the eighth The Land Before Time film turns out to be this. Originally respected as the smartest resident of the Great Valley, having "been everywhere and seen everything", he soon confesses to the kids that he gets most of his knowledge from second-hand sources.
Nim Galuu from Epic is only as powerful as the scrolls that write the forests' activities, which cannot predict the future, and can only record so much. In the climax, MK calls him out on how he's relatively useless on his own.
Moe of The Three Stooges is arguably the best example ever of this trope. He often rudely bosses Larry and Curly(and Shemp) around for goofing up and considers himself smarter than them but is clearly every bit as dim as they are.
Wanda: To call you stupid would be an insult to stupid people! I've known sheep that could outwit you. I've worn dresses with higher IQs. But you think you're an intellectual, don't you, ape?
Otto: Apes don't read philosophy.
Wanda: Yes they do, Otto. They just don't understand it. Now let me correct you on a couple of things, OK? Aristotle was not Belgian. The central message of Buddhism is not "Every man for himself." And the London Underground is not a political movement. Those are all mistakes, Otto. I looked them up.
Jimmy from Barbershop is only working at the shop to pay his way through college, and he tends to lord his superior education over his fellow workers. Problem is, he frequently gets his facts wrong, such as when he corrects another character by saying that scallops aren't mollusks (they are) and that a local store owner is Pakistani, not Indian (no, he's definitely Indian and quite resents being called Pakistani, thank you very much).
Inverted in The Monkees’ 1968 movie, Head. Peter, frustrated that the guys wouldn’t listen to him after warning them about the “Black Box,” makes them sit down to listen to his highly intelligent philosophy passed down to him by the Swami earlier in the film. His monologue closes with: “But then…why should I speak, since I know nothing?”
Paul, the "pseudo-intellectual" in the Woody Allen film Midnight in Paris acts like an expert on general Parisian art and culture, but is proven wrong several times. It doesn't stop him though.
Gran Torino: Invoked and played straight: Just after Walt accuses Father Janovich of being this after hearing his wife's funeral speech, Father Janovitch asks him what Walt knows. Walt realizes that he knows plenty about death, but not a lot about life.
Dr. Rick Marshall from Land of the Lost thinks he's an expert on everything just because he's a brilliant astrophysicist. At one point, he thinks dumping urine on himself will mask his scent, despite everyone pointing out how stupid that is. Indeed, the urine helps the dinosaurs find him faster.
Vizzini from The Princess Bride is openly enarmored with his perceived intellect, but it is clear that he knows far less than he pretends. He belittles the known great thinkers, he comes up with several far-fetched justifications for either cup the masked man may have poisoned (and fails to consider a third option), and keeps misusing the word "Inconcievable".
Neatly encapsulated in this lovely quote:
Man In Black: Truly you have a very dizzying intellect.
Vizzini: Wait til I get going! [beat] Where was I?
Shows up in 42 with a baseball announcer who declares that African-Americans are naturally faster runners than whites due to having a "naturally longer" heelbone. He gets mocked by his peers when Jackie Robinson hits a home run soon afterwards.
Animorphs: Rachel's mother Naomi, who doesn't adapt well to going from high powered attorney to camping with aliens and subordinate to her teenage nephew.
Not at first, but Naomi eventually proves herself rather useful, helping the Hork-Bajir draw up their own Constitution and persuading Captain Olston to lend his support to the team.
Gilderoy Lockhart from Harry Potter initially appeared to be one of these, although in the end it turns out he's well aware of his own incompetence.
Sergeant Colon from the Discworld series is a mild version of this. He does consider himself well informed, but the only person he tries to impress this on is Nobby Nobbs, who he's aware may be winding him up. Such as when Colon identifies hieroglyphs as a type of mollusk, and is asked if they go lower they'll find loweroglyphs, and decides to go for broke - everyone knows you don't get loweroglyphs in these waters. It is said he had a broad education; he went to the school of 'my dad always said', the college of 'it stands to reason', and is now a post graduate student at the university of 'what some bloke told me in the pub'.
Most members of the UU faculty also display a strong tendency towards this trope. Everyone, that is, save Ponder Stibbons, who occasionally fakes it, spouting his own ridiculous explanations because he knows the real facts will only kick off another off-topic argument among his colleagues.
Part of this phenomenon, in the case of the wizards at least, may be attributable to the fact that (much like real-life scientists up until about the turn of the twentieth century) they consider new breakthroughs to be gross discourtesy rather than something to strive for.
Yes, everyone except Stibbons, the Bursar (who can actually translate Stibbons' explanation into layman's terms), Ridcully (who is definitely Obfuscating Stupidity) and the Librarian.
And of those four, the Bursar is insane, the Librarian is an orangutan, and Ridcully is not averse to flying off into tangential arguments of his own. Though, again due to Obfuscating Stupidity, he could be doing that on purpose.
Granny Weatherwax does this as well, insisting that elephant is "a kind of badger".
Granny is well aware of her own shortcomings, but her 'Headology' requires her to make the common folk consider her nearly omniscient.
Becomes a point of Hypocritical Humor in Jingo, when someone in the crowd is saying questionable facts and Colon mutters "There's always a know-all."
Brother Verber, from Joan Hess's Maggody mysteries, recites Bible phrases at the drop of a hat. As he's the inept product of a fly-by-night correspondence-course seminary, he constantly misquotes them, mistakes their verse numbers, and/or takes them so far out of context as to be irrelevant.
This is the defining personality characteristic of Stingray from Toys Go Out and its sequel Toy Dance Party.
The character Jesse Honey, in Mark Helprin's Winter's Tale, thinks he knows everything but is laughably incompetent, and takes any critique as a shot at his diminutive height. It gets him and another character into trouble or injured several times, and eventually gets Jesse killed. Another character, Juliet Paradise, is a self-proclaimed intellectual who is noted to believe that a goat is a male sheep.
Mary from Pride and Prejudice can be read as one. The book implies that while she studies hard, she doesn't take in much and can learn the mechanics but not the soul of what she studies. It's shown most during the brief times she's allowed to talk, where she almost always moralizes about obvious things with all the arrogance and pride of someone making a great discovery.
Kirtan Loor from the X-Wing Series has a Photographic Memory and, because of it, thinks himself a genius and is always surprised when his plans don't work. Early in the series he's taken before the Big Bad and lambasted for his flaws, most notably a tendency not to think. For the rest of the series he proceeds believing himself to have changed, but one or two insights aside he really hasn't.
Most of the humour in Kaz Cooke's Little Book of X..er...books comes from the author taking this role, providing "advice" on whatever subject that is one million per cent useless. The Little Book of Beauty suggests the use of wood glue for hair care, for Pete's sake.
Mark Twain discovered one of these among his fellow passengers on the trip he took in The Innocents Abroad. Dubbed "The Oracle," his hilariously inaccurate observations (like pointing out "the pillows of Herkewls" in the Strait of Gibraltar) were encouraged by the other voyagers.
Adrian Mole considers himself an "intellectual" and brilliant author with a wide knowledge of art, literature, history and culture. In reality his writing (all unpublished) is terrible and he frequently confuses writers, important events, public figures and branches of the arts. He is also shown to have limited general knowledge, such as not knowing why someone called Pandora would have the nickname "Box", or thinking that someone in the UK could take a day trip to China.
British statesman Lord Chesterfield wrote about them in Letters to His Son: "coxcombs, who have no learning at all; but who have got some names and some scraps of ancient authors by heart, which they improperly and impertinently retail in all companies, in hopes of passing for scholars." (letter XXX)
In the Greyfriars stories, Billy Bunter lives and breathes this trope along with its accompanying trope, Ignorant of Their Own Ignorance, unless the plot requires him to (always temporarily) come to his senses.
Cliff Clavin of Cheers, to an extent that he was the original Trope Namer. He inherited his "gift of gab" from his mother, Ma Clavin. The big difference is that Esther actually knows what she's talking about, despite being a know-it-all herself.
Well ya see, Norm, it's like this. A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it is the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members. In much the same way, the human brain can only operate as fast as the slowest brain cells. Excessive intake of alcohol, as we know, kills brain cells. But naturally, it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine. That's why you always feel smarter after a few beers.
Cliff was not part of the original Cheers concept. He was added after John Ratzenberger went to audition for the part of Norm. He ultimately didn't get the part but, while he was there, he pitched them the idea for another character, a typical bar know-it-all. He improvised a performance to give them an idea of how the character would act, and that sealed the deal.
From time to time, he did actually get things right, and on other some other occasions he was cut off before he actually spewed anything that was incorrect.
John Ratzenberger said that, according to Cliff, Cliff was "the wing nut that held civilization together." According to Ratzenberger, Cliff is just a winged nut.
Britta Perry from Community wants to be seen as an enlightened woman of the world, but often betrays her ignorance.
Mr. Chekov, of Star Trek fame, thought that everything from genetically modified wheat to the written word was a Russian "inwention". Given that the show was made during the Cold War, he was never right about any of it. This is actually Truth in Television, as Soviet propaganda tried to trace many things to Russian inventors, to the point that people started joking that "Russia was the homeland of elephants", or the greatest inventor of all time, Lenard da Vishinski.
This attitude of Chekov was spoofed in a novel by Diane Duane, when he claimed that roller coasters had been invented by Russians. Nobody believed him, as the first roller coaster had been patented by an American... Yet, Russians actually created the ancestor of roller coasters, the Russian mountains, and in many languages (like Italian or Portuguese) the roller coasters are called the local language's translation of "Russian mountains".
In the original The Twilight Zone episode "Hocus-Pocus and Frisby" (under the late great Rod Serling), a small-town bumpkin was this, and everyone around knew it. Except the aliens (who had never evolved the concept of lying) who overheard him, mistook him for the greatest human brain ever, and kidnapped him for their zoo. He escaped through courage and dumb luck. And when he tried to tell people ... Crying Wolf, anyone?
For that matter, most TV pundits in the US are like this; parodying this was the original premise behind The Colbert Report.
Kathleen from Degrassi Junior High is a borderline case. She really does know more than the rest of the cast, but she's such a Control Freak that this knowledge is rarely relevant to anything. She drives a science fair judge crazy by reciting every stack of facts she knows, never giving her partner a chance to talk, and is shocked when that doesn't earn her first prize. A Running Gag on the show is that when Caitlin (the overachieving School Newspaper Newshound) needs to come down to earth a bit, it always happens by way of Kathleen doing something better than her — which is the most humiliating thing possible.
Parodied in The Red Green Show in the segment where they examine the three hardest words for a man to say: "I DON'T KNOW!" Thus, the guest is always morphed into one of these.
Played straight with Hap Shaughnessy who, in any episode that features him, claims to have invented a common item or to know the reasoning of historical figures due to him being there when they made their decisions (if he wasn't responsible for them making the decision in the first place).
In The Muppet Show, Sam the Eagle claims to value culture, but in reality he's a complete ignoramus with the arts. For instance, he didn't recognize the world famous ballet dancer, Rudolph Nureyev, in street clothes and thought William Shakespeare was a composer.
More recently, he tried to sing (karaoke, cause it's a nice American activity, even!) "American Woman" in one of their new YouTube videos. When the machine told him it was by The Guess Who, he hazards, "Um, I don't know...John Philip Sousa?" before trailing off halfway through the third or fourth line, demanding to know who was responsible for the blatantly anti-American lyrics. And he really flips it when Kermit tells him The Guess Who is a Canadian band.
Paul Kinsey of Mad Men. Perhaps his defining quote in the series wasn't actually said by him, but rather about him; "We get it, you're educated."
Charlie: This bar runs on trash. It's totally green now.
Dennis: How is burning trash green?
Charlie: I could stick it in a landfill, where it's gonna stay for millions of years, or I could burn it up and let it disappear into the sky where it turns into stars.
Mac: That doesn't sound right, but I don't know enough about stars to dispute it.
Danny Kaye had a number of characters who were this. Though most of them were one-offs.
'Yes, my friends, do you realize you can live to be a 127 years old... if you listen to Petrov?
First, you have got to live for a hundred and twenty six years. Then, you have to be very very careful'
Sheldon Cooper of The Big Bang Theory is normally a straight-up Insufferable Genius. However, once you get him out of physics and onto biology, his knowledge gives out very quickly. His opinion of his knowledge, on the other hand, does not.
Neelix of Star Trek: Voyager claims to be competent at many things (diplomacy, navigation, survival, cooking...) but he fails almost every task he's given. Sometimes it's hard to tell whether he's supposed to be this trope, or if they're Informed Abilities.
To be fair, Neelix is quite knowledgeable about the Delta Quadrant which is why he's the ship's designated guide. The comedy in the character comes from his desire to prove that he's more than just a tour guide. He's also a competent cook, it's his very limited selection of ingredients that make his food less than savory.
Foggy Dewhurst of Last of the Summer Wine has deluded himself into thinking that he knows the answer to any problem the trio is stuck in, when more often than not, he just makes things worse, mostly for himself.
Rory Gilmore of Gilmore Girls. Yes, Lorelai Junior. Although she excels academically, she is often lost in social situations.
In Downton Abbey, Robert hires Sir Phillip Tassel to assist in Sibyll's childbirth. The family physician expresses concern that Sibyll is suffering from Eclampsia. Tassel dismisses this right until the end, saying what she's experiencing is normal. The other physician was right, and Sibyll dies from Eclampsia. Yeah.
Bill McNeal from NewsRadio quite frequently. He once attributed the line, "Gather ye rosebuds while ye may" to the poet John Keats in 1776. Too bad that 1) that wasn't Keats, it was Robert Herrick, and 2) it wasn't written in 1776; in fact, neither man was alive then, Herrick having died in 1674, and Keats not being born until 1795.
Frasier: Roz's arrogantly ignorant hipster friend Jen, who, among other things, wants to go to Vietnam on vacation because "Americans haven't heard of" the country, and that an art gallery mostly focused on paintings of landscapes is intended to "make us feel good" about American "imperialism".
At least half of any given fandom regarding the fandom itself. Especially the “Stop Having Fun” Guys and Scrub in fandoms that have them.
Played straight and averted by 4chan. This is a product of the fact that users of some boards completely loathe all the other boards. Interest based boards commonly avert this, and are somewhat filled with level-headed individuals who are generally intelligent and well informed in regards to the board's topic (/co/, /tv/, /sci/, /lit/, and /a/ on a good day). The rest of the site tends to play this straight though, particularly the more easily trolled boards. /new/ is quite possibly the worst offender, as at least 50% of its userbase are superbly ignorant Neo-Nazis who spam The Bell Curve, with the other 50% composed of trolls posing as strawman liberals or conservatives.
RJ the raccoon from the comic strip Over the Hedge (not so much The Movie) makes up explanations for everything to the gullible woodlanders (to the annoyance of Verne, who usually has the accurate answer but can't explain it in a way anyone will understand).
Lucy Van Pelt of Peanuts. She thinks that snow falls up, fir trees have fur on them, and that a chain line is so that climbers can all fall of mountains and die together instead of it having the exact opposite purpose (so that the climber falling doesn't fall to his death because the others are holding him up).
Snoopy had some moments like this too. His rule of thumb whenever he got lost was that the moon is always over Hollywood.
A variant is Peppermint Patty; she'll get a dumb idea from a complete misunderstanding about something, ignore all common sense advice as she pursues this fixation until she humiliates herself and typically blames the people who warned her for not stopping her.
Calvin and Hobbes: Calvin's dad does this sometimes when Calvin asks him questions, but he's doing it on purpose. (Read: just making shit up and silently laughing at Calvin for believing him when he says, for example, that old pictures are in black and white because the whole world was black and white when they were taken.) Watterson's commentary says that he assumes it must be a great temptation for real parents not to abuse their power for pranks.
Then there's Calvin himself. Bats are not bugs, by the way.
Despite the picture above, Hobbes is not usually an example: math just isn't his strong suit. Why Calvin keeps asking him for help after all the bad grades he must get is something of a mystery.
Calvin is smart, but somehow is just unable to do his school work properly.
Howland Owl may be the best example from Pogo. But then, nearly everyone in the comic is absurdly ignorant and doesn't realize it.
The character of Dottore in classic Commedia dell'Arte is often played as smugly satisfied with his own learning, despite his ineffectiveness. In a script that cast him as a medical doctor, for example, he would speak perfect Latin, but his patients would all die.
This is Slightly's shtick in Peter Pan (and any incarnations thereof in which he appears). While none of the Lost Boys remember anything about life before they joined Peter's band, Slightly is constantly faking knowledge, convinced that he remembers himself.
Sheridan's play The Rivals gives us Mrs. Malaprop, who liked to use big words in an attempt to sound more educated than she was. She uses the wrong words, and Hilarity Ensues. Mrs. Malaprop's antics are the source of the word Malapropism.
Feste of Twelfth Night claims to avoid it because "it is better to be a witty fool than a foolish wit."
Kingdom Hearts's Axel gives hints of being this in 385/2 Days, when he talks about why the sky turns red.
By the way, Rinnosuke's supposed vast storage of knowledge comes almost entirely out of thin air. Indeed, he doesn't know nearly as much as he thinks he does. If you read closely, you'll notice a lot of wild, meta ideas, but I think that's supposed to be the joke.
Mao in Disgaea 3: Absence of Justice will frequently boast about having a 1.8 million E.Q (Evil Quotient), but is utterly clueless about simple concepts like love, truth, and friendship.
Disgaea Dimension 2 gives us the Krichevskoy Group, a trio of monsters that claim to follow King Krichevskoy's will and want to dethrone Laharl because they believe he's an Inadequate Inheritor. However, they don't seem to have a grasp on what made Krichevskoy a great and charismatic Overlord. At one point, they suggest using Sicily as a hostage to put the angels at a disadvantage which Laharl disagrees with and, considering the tropes associated with Krichevskoy, so would Krichevskoy.
Although it was reversed when the DM used the term "Vergence", which he thought he had made up but which Jim actually knew the definition of. Turns out he's not the idiot he seems, and is working on a Ph.D in geophysics. He just likes to "turn his brain off" when gaming, turning him into a Genius Ditz when something burns through the fog.
King Steve from 8-Bit Theater. Completely insane, but how do you argue with someone who "invented inventing"?
Kankri from Homestuck. He fancies himself as an authority on social justice, and will go on and on and on about class warfare and the injustices of the caste system - completely failing to realise that his society is free of such problems. He is also incredibly dismissive about other people's actual issues and social problems, despite priding himself on avoiding "triggers".
In Tails The Douche, Tails corrects Knuckles after he introduces himself as an echidna, telling him that it is pronounced "arachnid".
Ask That Guy is a particularly psychopathic version of this.
A less insane (butonlyslightly) version from the same site would be The Nostalgia Chick. Best showcased in the X-Men review, where normal!Chick brushes off Dr. Tease with "I know everything", and Chick on Truth Serum admits that the mutant powers really confused her as a kid.
Early SMBC Theater had this issue with subjects like Christianity, Superheroes and geek culture. However they have stuck with subjects they're more familiar with.
"Crank" is a pejorative term for a person who holds an unshakeable belief or opinion that most of their contemporaries consider to be false. Unlike the likes of Gallileo, Copernicus and Ignaz Semmelweis (whom Cranks may compare themselves to), whose theories were proven correct despite conflicts with established authorities, Cranks are characterized as overestimating their own knowledge and abilities irregardless of others opinions and experience, insisting their discoveries are urgently important while rarely if ever acknowledging faults no matter how trivial.
Starscream from the original Transformers was always lecturing Megatron about tactics, and naturally, was nearly always wrong (the episode "War of the Dinobots", in which Starscream is suspicious about the instability of the meteorite's energy long before Megatron ever has a clue, is among the exceptions).
Peggy Hill of King of the Hill, who is convinced she's perfectly fluent in Spanish, when she can't even speak as well as some of the students she teaches as a substitute teacher. She thinks she is incredibly witty and deep. She also feels a need to be the winner, or at least right all the time.
This is taken to its logical extreme in one episode, in which Peggy accidentally takes a Mexican girl home after misunderstanding her. After she returns the child, she's arrested and tried for kidnapping. She is ultimately acquitted after her attorney has her testify to the court in Spanish, showing the judge that she really did understand Spanish so poorly that the "kidnapping" had been accidental.
Best line in that episode?
Judge: *translated from Spanish* <Not Guilty>
Peggy: Oh God! I'm going to jail!!
Another running gag for Peggy is for her to make a very general or well-known fact and tack on, "In my opinion," such as, "The day after Thanksgiving is, in my opinion, one of the busiest shopping days of the year." Her tendency to take credit and boost her own ego eventually came back to bite her when Randy Travis plagiarized a song she'd mailed to him and everyone, including Hank, thought she was Crying Wolf.
In another episode, while Hank and Bobby are out camping, Peggy runs around nosing her way into everyone's business and telling them how they're wrong or trying to show how much smarter she is. Ultimately this results in her going into a crime scene like she's a Cowboy Cop and getting escorted back to her car as she protests "But I'm on a roll!"
Clyde Crashcup in The Alvin Show is a definitive example, claiming to have invented inventions that already existed, or being the first to discover things already discovered.
Brainy Smurf has a library of books, all written by him, all useless. Whenever he gives a useless lecture to the Smurfs, they throw him out of the village. He also insists that "Papa Smurf is always right."
The Simpsons: Though Lisa is very smart and knows stuff people don't already know, Homer and Lisa's argument at the dinner table in "Lisa the Vegetarian" has Homer calling his daughter a "barbecue-wrecking, know-nothing, know-it-all".
Homer also proves to know less than he boasts, particularly in the episode "Homer Goes to College," where he interrupts a professor's lecture on a proton accelerator; the teacher finally asks him to demonstrate because he must know so well how it works ... only for Homer to somehow cause a nuclear meltdown.
That was precisely what I was going to say myself.
On the surface Ruby may seem like this, but she does indeed seem to know exactly what to say, but hold it back to let whoever the other person is think it's their idea.
Patrick Star of Spongebob Squarepants would claim that Wumbo is a real word. He would also sagely detail the symptoms of Mad Snail Disease. He also knows that Spongebob is a zombie. Needless to say, it was all a load of barnacles.
Incidentally, as part of a Brick Joke, turns out Wumbo might have been a real word in Bikini Bottom, but one which fell into such disuse, only a old man like Mermaid Man can remember it (How Patrick knew about it is never explained). Then again, he is senile.
Brian from Family Guy especially in the later seasons he insists he's right about everything and pushes his beliefs to get everyone to take his side, and takes credit for ideas that weren't his in the first place and other times using them as an excuse in order to get into a woman's pants, as Quagmire put it:
"You pretend you're some profound intellectual but you're not"
Stan from American Dad! especially in The Most Adequate Christmas Ever, where he gets killed and fights his way up to God Himself in order to get brought back to life to save his family. As God points out, there's no better metaphor for "I know everything" than pointing a gun to God's head and insisting He's wrong.
In National Treasure 4: Baby Franny: She's Doing Well: The Hole Story, Steve convinces Francine to prove her worth by solving one of the Millennium Prize Problems in mathematics. After an intense mathematics montage, Francine goes up to a professor at a college lecture and announces that she solved the Yang-Mills existence and mass gap problem. Her solution? The number 6. The professor informs her that the answer wouldn't be a number, and she frowns and walks away.
Taz-Mania: Well-meaning and gregarious though he is, Mr. Thickley's assessment of his own expertise has absolutely no bearing on the reality of same.
Angelica from Rugrats always claimed to know more then the other babies and constantly filled their heads with false information.
She frequently gives them wrong information intentionally, however, since she seems to get a strange kick out of tormenting them with her lies.
Of course, more than once (like the chicken pox episode), something will happen that dupes Angelica into believing her own lies.
Dr. Lipschitz as well. He's apparently a famous child psychologist whose books are read almost religiously by parents, Didi in particular... but in the one episode where he appears, he obviously has little to no experience when it comes to working with children. He even claims at the end of that episode that he'll have to revise all his works because of the experience.
Cap'n K'nuckles from The Marvelous Misadventures of Flapjack. As an example, in "Careful What You Fish For" he convinces Flapjack that fish are a type of candy. After Flapjack licks the fish and says it doesn't taste like candy, K'nuckles 'explanation' is that this is because it's wild candy, not the store bought stuff Flapjack is used to.
Rocky and Bullwinkle had a regular spot called "Mr. Know-It-All" where Bullwinkle would demonstrate some skill for the audience, only to foul it up completely.