This is a common theme in advertising, since many people equate stupidity with frivolity and irresponsibility, traits that allow consumers to justify spending more money when they can't afford it, "just for fun."
Diesel clothing's current advertising campaign (as of February 2010) is: "Be Stupid."
Anime & Manga
The stupidest character in Sailor Moon is Sailor Moon herself, which is amplified by her laziness and whining. But she's typically the nicest and first to reach out to those in need.
Gourry Gabriev from Slayers is definitely not the sharpest knife in the drawer (a fact alluded to on numerous occasions) yet he comes off as just about the most easygoing, honest, and unobtrusive member of the permanent cast, especially the infinitely smarter but infinitely more jerkish Lina. In the original novels he was actually very much a Deadpan Snarker, and it was Obfuscating Stupidity, which he did mostly because it was funnier that way.
A recurring theme in Kinnikuman. Many of Suguru's opponents, prior to their Heel-Face Turn, are shown to be genuinely more intelligent than him. They also have plenty of techniques that they have spent time developing, whereas Suguru initially won with nothing short of dumb luck. For example, he won his first wrestling match simply because his opponent laughed so much at his ugly face that he broke his back. The final Big Bad is the ultimate embodiment of this trope, with Kinnikuman Super Phoenix being empowered by the God of Intelligence.
Son Goku from Dragon Ball. It gives you a clue if naive Goku who doesn't even know the difference between boys and girls can ride on Nimbus, a cloud which only allows those pure of heart to ride, while Bulma, quite possibly the smartest female on the planet, can't.
To quote Goku:
Goku:(to Frieza) I'd rather be a brainless beast than a heartless monster like you.
One reason Goku isn't as violent as the rest of his race is because he suffered a severe head injury when he was a baby. So he's only a good guy due to head trauma. The villain from the Non-serial movie The Tree Of MightTullece is essentially a look at what kind of person Goku would have become if he hadn't cracked his skull. He's pretty much identical to Goku physically and shares similar love of food and drink, but he's an intelligent and utterly twisted villain.
Monkey D. Luffy of One Piece is pretty dumb but certainly is one of the most fun-loving and nicest characters you'll ever meet. The smartest characters are either greedy and selfish (and this is just a description of those in his crew), manipulative, sadistic, homicidal, and schematically vile. And that's not even mentioning Sir Crocodile and Enel.
Tohru Honda from Fruits Basket. She's very naive/dumb and thus never even realizes that taking advantage of people can be advantageous, or more accurately she's so air headed it never crosses her mind. Her air headed goodness is constantly put on a pedestal in the manga. This is later noted by Momiji telling the fable of the happy fool in volume three, he makes a direct link between the happy fool and Tohru. This is put on a pedestal when Momiji proclaims that the happy fool is the one truly blessed..
The title character of Naruto typically uses his brain last in dealing with any given situation, but it's usually because he acts from the goodness of his heart before anything else. This is a sharp contrast with many of the more intelligent characters, such as Sasuke, Neji and even Sakura, who are generally colder and meaner when they are first introduced (at least at first).
The First Hokage Senju Hashirama. A tremendous shock to fans and to the ninja who find this stern, noble historical figure cracking bad jokes, going off on tangents, and sulking like a five-year-old.
Uchiha Obito. His personality is nearly identical to Naruto. Interestingly enough, on becoming Big Bad Tobi, he also becomes smarter.
Tamaki from Ouran High School Host Club. While it seems that he somehow manages to rank in the top ten in academics in his class every year, that brilliance is definitely not portrayed in daily life. In fact, the characters often make comments about what an idiot he is. At the same time, however, he seems to be one of the nicest guys in the world, constantly doing things for other people and trying to make them happy.
Nobita Nobi from Doraemon has the lowest grade in classes, and is an overall nice guy of the main casts as long as he's not bullied too hard.
Lucky Star: While Miyuki certainly owes her sweet nature to her mother, it's clear the woman is not responsible for her daughter's intelligence. She'll happily start a conversation with telemarketers but according to Miyuki, she had to mature fast because her family wouldn't be able to function with just her clueless mother running the house.
The titular character of Yotsuba&! isn't stupid for a five year old child. But there's a very large number of things she doesn't know, and she's very good by any definition.
Akihisa Yoshi from Baka and Test: Summon the Beasts is the baka (read: idiot) of the title, but what he lacks in brain cells he makes up for in heart. Only he would think stealing back his confiscated stuff from a teacher in order to pawn them off to buy a little girl a stuffed animal for her sister would be a good idea. His dumbness infuriates his female friends but his pure actions and motives unwittingly win him their hearts.
Jeremy, from The Adventures of Barry Ween, Boy Genius by Judd Winick, has a tendency to eat things he really shouldn't eat, gets himself into trouble that Barry has to bail him out of more than a few times, swears constantly especially when it's least appropriate, and definitely isn't Barry's intellectual equal (though to be fair, nobody is). However, he's consistently shown to have a stronger moral compass than Barry himself, and acts as Barry's Morality Pet and conscience. He's also called out Barry on some of his more callous actions. It's heavily implied that Jeremy's friendship is one of the only things keeping Barry sane and keeping him from becoming a full blown Mad Scientist.
Likewise in Ultimate Marvel, Hulk defeats Abomination because the latter "thinks too much."
In one Garfield strip, Garfield berates Odie's vapid stupidity and rhetorically asks who could possibly love a grinning idiot like him. Cue a sudden downpour that soaks everything. Everything but Odie, who is somehow shielded from the rain.
Garfield (while looking up at the sky):You stay out of this!
Rocky Balboa from Rocky so embodies this trope that many fans forget he was a leg-breaker for a loan shark in the first movie. Of course, he was never shown breaking legs for the loan shark, and he refused to break a man's thumbs. Diminished later on the series when he became a mentor figure, to the point where one reviewer commented that he was the only boxer to become smarter the more he got punched in the head.
Very common in most Abbott and Costello movies, shows and routines. Abbott is clever, mean and sly and Costello is usually dumb and happy or at least naive and happy-go-lucky.
Forrest Gump has Forrest Gump. His characterization is aimed more toward satire in the books, which play up Gump applying his uncomplicated, bullshit-free worldview to all the craziness going on around him even more than the movie did.
Parodied effectively in Tropic Thunder with Tugg Speedman's "Simple Jack" role.
Being There (and Chance the Gardener's character type in general), both the original novella and the film version, is something of a subversion of this that ironically predates the above. Chance is a good-hearted fool, but he affects intelligent-but-unhappy people only because they think he's intelligent, and his concrete statements are thus interpreted as grand metaphors.
Rock and Roll High School is about the struggle between an authoritarian, rock and roll-hating, principal who complains that students aren't learning in gym class with a Ramones-loving, rabble-rousing, Book Dumb student who leads the rest of the school (including one teacher) to trash the school, then blow it up with explosives. This is portrayed as an unequivocally good thing to do. The main character's best friend, however, is supposedly a genius who works on nuclear physics in her spare time
Stan Laurel in Laurel and Hardy is usually shown as happier and nicer than Ollie, as well as dumber — not that Ollie was massively smart either. Notably, in A Chump at Oxford, becoming smart turns Stan into a jerk. Funnily enough in real life Stan Laurel was an intelligent "ideas man" and Ollie was more easy-going and not as clever as Stan (but considerably cleverer than he portrayed himself in films).
The Adam Sandler movie Little Nicky has the main character being the good dumbest son of Satan borne out of a fling with an angel while his other brothers Adrian and Cassius are both smarter and stronger respectively. Evidently took after his mother since all the angels are blond, ditzy valley girls.
Elwood P. Dowd: Years ago my mother used to say to me, she'd say, "In this world, Elwood, you must be" — she always called me Elwood — "In this world, Elwood, you must be oh so smart or oh so pleasant." Well, for years I was smart. I recommend pleasant. You may quote me.
This is savagely deconstructed on the Mexican film La Ley de Herodes, more specifically the now Dead Horse Tropes from films where a naive, yet well-intended protagonist is manipulated by meaner corrupted people and manage to beat them with goodness showing that: 1) This is highly unlikely to happen in Real Life and 2) How the protagonist gets more and more corrupted until he become far worse than the corrupted people that manipulated him as a mean of survival.
Regarding Henry is probably in a class by itself. Harrison Ford plays an arrogant prick of a lawyer and a bad husband, until he gets shot in the head!
A fairly mild example in Barbershop, where all the characters who work in the titular shop are generally "good." But the one college educated barber who defines himself by his brain is also the one who's closest to a Jerk Ass. He's treated as something of a Butt Monkey by the other barbers, and when the somewhat thuggish character Ricky takes him down a peg the whole shop considers it a Crowning Moment Of Awesome.
The "Smart people are mean, dumb people are nice" dichotomy is best illustrated in The Lawnmower Man. The protagonist starts off as a sweet, nice, likable mentally handicapped young man. As the story progresses, the more intelligent he gets, the meaner and more malevolent he becomes.
In Tommy BoyChris Farley plays a lovable dunce while his counterpart, David Spade's character, is referred to as "a smug unhappy little man [who treats] people like they're idiots."
Deconstructed in Billy-Bob Thorton's written, directed, and starred in film Sling Blade, where he plays the mentally disabled man Karl Childers. Karl is kind, soft spoken, and blind to intolerance, and is also a talented mechanic because he always finds the simplest solution to problems. However, he also has no quams about brutally murdering people he deems to be bad.
Inverted in Pain and Gain, where the protagonists are incredibly dumb greedy murderers who succeed mostly on sheer luck while the Hero Antagonist Ed DuBois is apparently the only intelligent person in the entire movie.
Baube Lud from Felsic Current is very dumb. Therefore, despite the mocking of his fellow troopers and his failed attempts at romance, it never occurs to him to be anything but fundamentally good-natured and good at his job. Very good.
A precept of The Party in 1984: "Ignorance is Strength". People are encouraged to not think in order to have better lives. It's because smart people will question the system, realize it sucks, and possibly revolt.
John Steinbeck's Of Mice and Men sets this up: Lenny is the childlike of the pairing, while smarter Curly is an intelligent villain. Slim describes the concept directly, some way through the book.
Inverted in the first of Larry Niven's The Magic Goes Away stories. The hero is a wise, intelligent sorcerer who happens to call himself "Warlock"; the villain is a barbarian with a magic sword.
Inverted throughout A Series of Unfortunate Events: it is stated outright that "well-read people are less likely to be evil". The villains are Book Dumb at best and often shown to be complete philistines who prefer the maudlin, sentimental writing of Edgar Guest to great works like Moby-Dick. Olaf is shown to be unable to spell "poison". Two characters who seem to be evil masterminds identify eagles as mammals.
Fezzik from The Princess Bride, although Inigo turns good, too. In fact, one could argue that Vizzini is the stupid one. The book Vizzini is legitimately portrayed as a twisted genius (who, in the end, gets tricked into outsmarting himself).
Blaggut, the illiterate, less-than-bright searat in The Bellmaker, the only vermin in the series to survive a Heel-Face Turn. He's initially paired with the captain from his ship, who obeys the usual Always Chaotic Evil role of vermin, but eventually kills him when the captain murders the abbey's Badger Mother.
The Discworld novels will occasionally feature a stupid, more sympathetic Dumb Muscle villain (Banjo of Hogfather, Lemon of Soul Music, and Mr. Tulip of The Truth all leap to mind) who gets a more favourable end than his cunning partner in crime, but this is more to show how easily stupid people can be led astray. The heroes are usually quite intelligent.
Possibly played straight with Brutha from Small Gods. Despite his fantastic memory, he is considered a bit dim by most other characters. Nevertheless, he is compassionate and noble, and is the only one of Om's many worshipers to actually believe in him. It may be that his simplicity is the reason he never questioned what he was taught to believe (as opposed to everyone else, who simply go through the motions out of tradition and fear).
This is explicitly subverted with the characters of Carrot and Vimes. Carrot is a good natured, kind, and generally optimistic person who is often described as "simple". After this description, however, the books never forget to mention that "simple" doesn't mean stupid, and as the books go on it is clear that Carrot has an incredible deductive mind. Vimes, on the other hand is a cynical grouch who has little use for most people around him, but it's made clear that he truly loves his city and those who work under him, not to mention his wife and son.
Angua: Someone has to be very complex indeed to be as simple as Carrot.
Vimes is often regarded by others as not very bright, but he makes up for it through a combination of obstinacy and being Dangerously Genre Savvy.
Cohen and his 'horde' from Interesting Times can't exactly be called smart (except for 'teach'), but they are extremely skilled fighters.
All of these simple-but-good examples could be considered cases where wisdom contributes to goodness more than intellect.
In Flowers for Algernon, protagonist Charlie Gordon is a mentally challenged man mocked by most of the people he knows for being retarded. Then he participates in an experiment that makes him a genius, except he's still alienated because most of the people in this world are now half his IQ, so he can't relate to them. Plus, they're frightened/frustrated/jealous of his superior brains. The difference is that when he was retarded, he didn't realize when people were making fun of him, so he was able to be naive and happy. Then when the experiment fails and Charlie regresses to an IQ in the 70s, he becomes happy again and people start liking him out of pity.
Caramon Majere, of the Dragonlance series, is perhaps best described as a lovable oaf: Friendly, outgoing, not exactly bright but everyone likes him. Raistlin Majere, on the other hand, is a Deadpan Snarker who spends more time with his spellbooks and his bitterness, recognized as a magical and intellectual genius who spends most of his time ordering Caramon around. And this is before Raistlin undergoes his Start of Darkness!
The Lord Dunsany short story The Bureau d'Echange de Maux centers on a The Little Shop That Wasn't There Yesterday where people can exchange any burden they felt they had. One pair exchanges wisdom for folly and folly for wisdom. The man who gave up wisdom is described as leaving looking happier than when he'd come in.
The Wolfs in The Talisman appear to be of universally low intelligence but are extremely loyal to the king and the crown and very friendly people. Since they're huge powerful werewolves, Morgan of Orris tries to corrupt some to his side.
Brandon in ''The Leonard Regime. Despite being dumb, he still fights for liberty. Also, he is never the aggressor in his arguments with Nick.
Taranvigian in The Stormlight Archive works like this. Due to a magical effect, his intelligence shifts from day to day, and his morality is inversely related. This is explicitly part of the effect, as he notes himself that it doesn't work like that for most people.
Live Action TV
Angel: The Groosalugg. He eventually wises up to this and lets the rest of the team do the planning.
In the Farscape episode "My Three Crichtons", the hyper-evolved and super-intelligent version of Crichton is the least compassionate. The caveman-like Crichton, on the other hand, is the most moral, even doing a Heroic Sacrifice to save the regular Crichton's life
The regular Crichton, however, is actually legitimately intelligent (the Farscape project was to test a physics theory he came up with, after all) and fairly nice, being one of the more moral characters in season 1. Most of his crewmates think he's a moron (at first at least) thanks to being unfamiliar with the sector of the universe and his constant pop culture references
Malcolm in the Middle explicitly explored this in one episode, with stupid older brother Reese teaching Malcolm how to "turn off his brain" by singing commercial jingles to himself all the time so that boy genius Malcolm would be happier, kinder, and more relaxed. It works until Malcolm finds himself in a situation where he needs to think quickly and he abandons his blissful ignorance to return to his intellectual, cynical, Jerkass persona. Of course, Reese himself is an aversion. Dumb he is, but nice he ain't.
The original page quote was a "No one likes the smartest kid in the class" line from The West Wing. Regardless, Aaron Sorkin does not so much subvert the trope as reject it, shoot it, string it upside down from a lamp post and spit on it. Much of Seasons Three and Four witness President Bartlet and his staff rejecting anti-intellectualism and extolling the virtues of education and intelligence. It's a measure of what we normally see on TV that "extolling the virtues of education and intelligence" actually makes the show unique.
See also Aaron Sorkin's Studio 60 on the Sunset Strip, in which a sketch is called "boring" in a focus group. When another member of the group calls it "too smart," it's pointed out that "smart is another word for boring" and Simon snorts, lamenting "smart as a pejorative."
In particular, his seventh and tenth incarnations both have a nasty reputation for manipulating companions and civilians alike; the only differences between the two of them is that the seventh (who's a lot better at it) will usually have a better reason for his manipulations.
Seemingly played straight in "The Long Game" with Adam Mitchell, though it's that he uses his intelligence to try to profit by stealing future technology to "invent" in the present, which would heavily disrupt the established timeline.
Many companions, both temporary and long-term, have been notably intelligent or tech-savvy by human standards, such as Martha Jones and Rory Williams.
The episode of The King of Queens "Educatin' Doug". Carrie enrolls herself and Doug in an English night class (which Doug isn't too thrilled about) when she thinks they're becoming TV-addicted idiots. Carrie does quite well in the class, but Doug struggles, resorting to beat the information he needs out of Spence, who is also in the class. At first Carrie is angry when she finds this out, but eventually learns that she shouldn't have forced Doug into the endeavor. In addition to Dumb Is Good, the Aesop here would also seem to be "Leave well enough alone".
In The Unusuals, there's a repeat offender named Marvin who's so stupid he commits crimes wearing a necklace with his name on it in huge gold letters, but he's portrayed as not such a bad guy because he's just too stupid to be malicious.
In one episode of the 1990s Outer Limits, Doogie Howser plays a man whose mental retardation renders him immune to Id-unleashing parasites.
Kieth has problems in Like Family when he moves to a place where people don't have this attitude.
In the soap opera All My Children, cunning (often) villain Adam Chandler had a twin brother Stuart who was both very sweet and quite dumb.
In Eureka, Sheriff Carter is frequently shown finding solutions to problems that none of the geniuses around him can't find.
How I Met Your Mother: Ted seems to be at his most annoying when he's displaying conspicuous intellect. He even acknowledged this himself in one episode, recognizing that he was being a "douchebag" when reciting (from memory) Dante's Divine Comedy in the original Italian, a legitimately impressive achievement.
Invoked on Family Matters when Eddie and Laura set Laura's friend, Maxine, up with Waldo Geraldo Faldo. She was initially put off by his stupidity, but in the end, she found him at the same time to be a charming and sweet guy. The continued to date until Waldo was eventually Put on a Bus.
P!nk's "Stupid Girls" criticises the trope and urges young women to think and have ambition in life.
Averted many times in Dilbert. The negative consequences of stupidity is probably the most recurring theme of all, and the majority of the strips deal with the protagonist's struggle against his obtuse colleagues and bosses as well as the kafkaesque workplace they inhabit. Paradoxically, you could also say that the trope is played straight at the same time, as there are several occasions where intelligence and skill is portrayed as a serious (and sometimes fatal) drawback.
Jesus himself defies this trope while instruction the Twelve Disciples in Matthew 10:16 — "I am sending you out like sheep among wolves. Therefore be as shrewd as snakes and as innocent as doves."
A major tenet of Imperial dogma in Warhammer 40,000. "Thought Begets Heresy; Heresy Begets Retribution" and "Only the Awkward Question; Only the Foolish Ask Twice" are two common quotes in the fluff. Within the metaphysics of the universe, close-minded dogmatism is one of the only things that can stopa normal human fromfalling to Chaos.
Ogryns follow this tenet without knowing it. They have blind faith in the Emperor, and while some fought on the wrong side during the Horus Heresy, it is highly suspected that they were lied to about which side they were on.
In Backyard Sports, Pete Wheeler, who is dumb, is actually extremely nice. Dmitri Petrovich, who is incredibly smart, is mean. Averted with Reese Worthington, who is smart but nice (and is not a nerd).
Felicia has been generally established as the nicest and sweetest main character in the Darkstalkers series. Her appearances in other games, however, repeatedly suggest that she's also The Ditz on an almost painful level.
Inverted in I. M. Meen where the antagonist is an evil wizard who can't spell and hates studious children while the protagonist is one such child, described throughout the game as 'smarty' and 'bookworm'.
Subverted in Portal 2 with Wheatley. Though he does a Face-Heel Turnupon gaining control of the Enrichment Center, it takes literally seconds before he goes power mad. We learn from GLaDOS that he was built to be as unintelligent as possible to hold her murderous tendencies back. He attempts to trick and kill Chell and does not care that his actions (or lack thereof) will cause the entire Enrichment Center to blow up. Ultimately he's plagued by poor common sense regardless of his morality.
Throughout Portal, there's this distinct vibe concerning Prometheus. In the mythology, Prometheus was definitely lacking in hindsight, his brother, Epithemus, is lacking in foresight. GLaDOS never learns from her mistakes, only altering her modus operandi in the later half of the game. Wheatley takes the role of Epithemus. Definitely learning from the mistakes of GLaDOS, but rarely thinking ahead to formulate plans or traps.
Radiata Stories: Clive, a country hick, is one of the nicest guys in the game. Not only will he be Jack's friend without a Fetch Quest but he'll come to the guild and volunteer.
Duster in Mother 3, especially when compared next to Kumatora. Duster is portrayed throughout the game as dumb, but never fails to be a nice guy. By contrast, Kumatora, the smart girl of the group, is rather cynical and has quite a bit of an attitude.
Red vs. Blue. None of the characters are incredibly smart, but Caboose, who is dumb as they come, is definitely the happiest of the bunch, as was once commented on by Church. Also, he seems to try to be helpful to his teammates, but, well, he's Caboose.
Church: Dang man, I would love to live in your world for like ten minutes. Caboose: Yeah. I have a really good time. Church: Yeah it seems like it. I don't think I'd get anything done, but I don't think I'd care.
Grif is surly, uncooperative, and would, in general, rather not be here (wherever here happens to be at the moment). He's also been noted to be the smartest member of the Red Team (although, all things considered, this is more a judgment on his teammates rather than being particularly complementary towards Grif).
Similarly, Donut is usually very happy. One could even call himgay. He's only marginally smarter than Caboose. Their happy yet simple natures allow them to quickly become friends when Donut is captured.
This is played with, though not directly touched upon in 8-Bit Theater. Of the four protagonists, three are self-serving rogues who are often commiting or willing to commit actions far worse than most of their antagonists. The only character who could conceivably be called a hero is the one oblivious enought not to realize that his companions are incapable of altruism and that their schemes are often evil. However, it should be noted that he is sometimes shown to be a Genius Ditz and the other members aren't really that smart either.
However, outside of the main cast, Whitemage stands out as an example of a character who is both good and quite canny. Meanwhile, several very stupid characters are shown to be malicious, some of whom [King Steve] are capable of real harm while others are largely harmless due to their incompetance [but not for lack of intent or the internal frustration and bitterness which most happy-go-lucky heroes avoid]. So on the whole it seems like the trope is averted but played with to a degree as the stupider villains are often treated as harmless while Fighter remains a good guy but may at times cause as much harm as his evil cohorts without realizing the consecquences of his own actions.
Nodwick goes both ways: Piffany seems to have severe problems with understanding what goes around her but is practically a living saint. On the flip side, Yeagar isn't much better but is the only party member to be actively malicious. Artax and Nodwick, the two most clear-headed thinkers in the party (in that order) are both Deadpan Snarkers to various degrees, but Artax is considerably more callous than Nodwick. Thus, the dumbest and the smartest person in the party are the nicest, with the two in the middle picking up the "nasty" slack (although Nodwick has an extremely caustic tongue, particularly in regards to Yeagar and Artax's antics). And Yeagar and Artax are the ones slapping Nodwick around. Repeatedly. While Piffany isn't looking.
Thog of The Order of the Stick is a subversion, particularly in this strip, whose title is Stupid Isn't Always Cute. This doesn't stop most fans being sympathetic towards him nonetheless. (Not that it's hard to be sympathetic in comparison to Thog's usual company).
Elan and Monster in the Darkness are relatively straight examples, especially early on where they were both the moral centres of their respective teams and the dumbest. However, both have gotten a lot more canny over the run of the comic and neither show any signs of bitterness or jadedness; though admittedly this is more genre-saviness than book learning.
Xykon plays with this, in so far as while he is still both intelligent and evil, he avoids the bitterness and other baggage that comes with this trope as he is often shown to not care about angst or strategy so much as just having fun being evil.
In The Last Days of FOXHOUND, the biggest jerks in the comic tend also to be the smartest (excepting perhaps Raven) — Otacon is the best example in that he is the series' perhaps only genuinely good person, and also a complete Ditz.
This is parodied in Happy But Dead. When Tito, Gear and Colin die, Colin and Gear go to Hell. Once there, they learn that Tito made it into Heaven despite doing just as much bad stuff as they did. However, as he was considered too stupid to fully understand what he was doing was wrong, he automatically gets a free pass to Heaven.
This ideal is actually promoted by Captain Hammer himself in the comics, with him stating that smart kids or anyone that doesn't immediately fit mainstream's perception of normal should all be thrown into jail. The audience of course is expected to know that he's just spouting [BS].
Generally averted in the Whateley Universe stories. The (high school) protagonists are all intelligent and also good, with about half of them in the genius category, and several of them seriously focused on scholastic achievement. Some of the worst people on campus, like Buster, are the dumbest.
Ed, Edd n Eddy: Both Ed and Eddy despise and make fun of Edd's High IQ/Intellect in almost all of the early episodes, for two reasons:
1. Seems to have problems in regards to thinking ahead.
2. It also can be said, Edd seems to be fairly arrogant, sometimes.
It should be noted that Double D wasn't really presented as the clear "smart one" until the latter end of the first season.
Eddy is much more arrogant and insufferable than Double D (which is saying something) but certainly not quite as smart.
Also Double D seems gets more flak (particularly from Eddy) when his intelligence isn't up to par. "You're messin' with the group dynamics" and "you really haven't been on the ball lately".
Edd actually averts this. He's a genius, but he's incredibly nice most of the time, up to the point that the other neighbors tolerate him the most out of the main trio. He is often portrayed as sensitive, thoughtful, and reasonable.
Dexter of Dexter's Laboratory. While he's less of a Jerkass than rival genius Mandark, Dexter is still high-strung, arrogant, and seems to have problems in regards to thinking ahead. In contrast, his older sister DeeDee is usually much more cheerful, sensible (sometimes) and laid back, despite being something of a Cloudcuckoolander.
Pinky and the Brain. Pinky being the dumb but nice and happy one, while Brain being a dour super genius hellbent on taking over the world. Played with when Brain makes Pinky intelligent and, finding out that an intelligent Pinky is actually smarter than him, comes to realize he is the reason they always fail (proved mathematically no less) and reduces his own intelligence. The subversion is that Pinky is still happy, energetic, and full of "Narf" when he is intelligent while the Brain, though he does suddenly find rather silly things funny all of a sudden, retains his unhappy personality.
Gunter the chimpanzee from the episode of Futurama "Mars University". When he wears the bowler hat that Professor Farnsworth invented that makes him super-intelligent, he's a snobbish know-it-all, especially towards Fry. Later, when Gunter's hat gets broken and thus only gives him average intelligence, he finds that he's much happier that way and decides to attend business school, much to Farnsworth's ire.
Mars University also parodies this trope with its motto,"knowledge brings fear."
The Simpsons episode "HOMR", in which the normally stupid Homer gets a crayon dislodged from his brain, making him slightly more intelligent than average (Homer: Is there no room in the world for somebody with a 103 IQ? ) . However, he quickly loses his friends due to his intelligence. Then Lisa tells him the sad "truth": As intelligence goes up, happiness goes down. Smart Homer sees only one recourse — re-insert the crayon through his nose...
Lisa is consistently (and for some, obnoxiously) portrayed as both the most intelligent and morally upright person in the family. She is frequently disliked by classmates and feels isolated and depressed as a result of her intelligence. She might sometimes save all of Springfield and be right a lot (at least, in the view of the writers) but she pays a heavy cost. Maybe the message is that Dumb Is Good most of the time, but you also need smart people around to occasionally save your ass.
One episode had the people with the highest IQs put in charge of the town. It was a complete disaster, largely due to their arguing over who was the smartest.
Ned Flanders is this trope. Ned isn't smart like Lisa, but he always sticks to his Christian values in doing the right thing and being a good neighbor to everyone, which gets him labeled as an extremely boring guy and Homer is constantly annoyed by him. Even when Homer or someone else tries to show Ned how to have a good time, Ned doesn't know how to relax or let loose because he fears doing something un-Christian may get him condemned to Hell or the like.
Invader Zim fell afoul of this trope accidentally with the character of GIR, a Robot Buddy at extreme levels of stupidity. Intended to be merely an idiot hedonist, he was seen as one of the nicer characters in the series, and an entire episode was dedicated to sticking him in "duty mode," which had the result of making him several times more evil than Zim himself. It didn't stick. Played more straight with Keef, who's completely oblivious to the fact that Zim doesn't like him, but one of the only nice kids at Skool.
Mongo in the Heathcliff cartoons was generally the most gentle and good-natured of the Junkyard Cats, as opposed to all the other characters whose main interests were some level of scheming and fighting.
Played with in Animalia, where Alligator actress Alegra becomes highly intelligent after accidentally absorbing Livingstone's intelligence, causing her to suddenly become a dangerously Evil Genius, to the point Livingstone's rival Tyranicus ended up helping the protagonist to get the intelligence back because he'd rather have his rival in perfect state than an intelligent Alegra.Partially subverted in that Alegra wasn't really a nice person to begin with (though her normal self does displays a softer side occasionnally), whereas Livingstone, when possessing his natural hight intelligence, is portrayed as an extremely wise and kind person. As such, the message would rather be that intelligence is a gift that can cause as much harm as good, depending who's possessing it.
Gorillaz gives us 2D, who isn't too bright, but definitely a nice person; he's a supporter of the Free Tibet campaign, and fans often comment on how adorably innocent he is. Moreso than Murdoc, his crazy and amoral bandmate.
Paula Cracker (talking about 2D in this interview: He was very sweet. A bit thick, though.
Tendril of the Inhumanoids was both the least intelligent and the least evil.
The Powerpuff Girls averted this with Mojo Jojo. Though he claimed he played it straight to guilt Professor Utonium into giving him superpowers, the Professor remembered that Mojo was always a destructive little monster. The Professor even claims that Mojo hasn't changed a bit since the first thing Mojo did with his new powers was to go on a rampage in the Professor's lab.
Inverted in real life. Criminals and delinquents have below-average intelligence by somewhere between half and a whole standard deviation, on average, meaning that being dumb makes you more likely to be evil. Interestingly, the Flynn Effect has increased the average IQ of people in developed countries over the last century, and those countries have warred considerably less with one another in the meantime.
There seems to be an unspoken assumption in American politics that "intellectual" is a synonym for "elitist," and therefore of "bad." This belief seems to be roughly traceable to the 1952 presidential election, which Democratic nominee Adlai Stevenson lost in a landslide partly because of his public image as an "egghead." Since then, it has become something of a ritual in American politics for presidential contenders in both parties to compete for which candidate can seem the most like "just regular folk." This gets particularly funny in those elections when both candidates went to Ivy League or similarly acclaimed schools.
It seems to hit a peak of ridiculousness during the 2008 Democratic Primaries, when the two front runners, Hillary Rodham Clinton and Barack Obama were both getting painted with the elitist brush, since they were both well-educated Law school graduates. It created the surreal images of Hillary Clinton drinking shots in a bar, all the candidates appearing on Saturday Night Live and The Tyra Banks Show, and other related weirdness.
Likewise it was major factor in the Republican Primary of 2008, prior to Mitt Romney's eventual victory many of the candidates tried to play up "folksy" images of themselves.
There is the old saying "A little knowledge is a dangerous thing, and Ignorance Is Bliss." That's gotten more important with the spread of easily accessible information. Depression is on the rise (or is being noticed more readily), and some blame the abundance of information. Some people have suggested the way to improve this is to "play dumb" and avoid the news before the worries of the world crush you.
This saying is actually misquoted and misunderstood, "a little knowledge is a dangerous thing...there shallow draughts intoxicate the brain", or, "an idiot with a little knowledge thinks he's an expert and acts like an Insufferable Genius because of it". Basically, if you're going to learn, strive to learn everything, so you know how little you really understand, but if you only learn a little you'll assume you understand everything. It's the difference between being a Know-Nothing Know-It-All and an actual expert in something.
Entertainingly, this has actually been verified by science: statistically, people with minimal knowledge of a subject are much more confident in their opinions regarding that subject than people that actually have any real level of understanding. This is named the Dunning-Kruger effect after the scientists that verified it, though whether they 'discovered' it is an open question since many cynical people have made the observation in less-scientific contexts throughout history.
Emma Watson (who plays the above mentioned Hermione Granger) has openly spoken against this trope, saying "There are too many stupid girls in the media. Hermione's not scared to be clever. I think sometimes really smart girls dumb themselves down a bit, and that's bad".
A deadly application of this trope happened in Cambodia during the reign of Pol Pot's Khmer Rouge where intellectuals were among the people singled out as enemies of the state and slaughtered en masse. Often the criteria for being labelled a intellectual involved something as simple as happening to wear glasses or looking "scholarly."
Similar example: a major tenet of the Chinese Communist movement was, for a while "kill all the intellectuals" almost in so many words. Then they realized that they'd killed the majority of their scientists and engineers and they needed roads and bridges, which is why most of Chinese infrastructure is now designed by contract labor from other nations. This is also why many students choose to attend a university outside China; a foreign degree, especially one from the United States, is highly valued.
The USSR under Stalin also enforced the hell out of this trope, the most well-known example being sending all the scientists that believed in natural selection to Siberia because it 'wasn't communist enough' and forcibly substituting Lamarckian evolution (proved wrong about 100 years earlier) into the curricula.
Interestingly, the earliest examples of the word "nice" being used to describe someone in the English language indicate that the original meaning of the word was "naive" or "innocent", or in other words lacking knowledge. For example, saying "What a nice child." would be describing the child as ignorant and carefree. So a word used to describe someone as dumb morphed into one used to describe someone as good.
King Henry VI of England was mentally impaired, and had little understanding of the war that was breaking out around him. Many at the time regarded his condition as pious innocence, in contrast to the machinations of the nobles around him.