Inverted in Metalocalypse; Toki Wartooth, Dethklok's rhythm guitarist and almost-literal second-fiddle to Skwisgaar Skwigelf, has an entire episode devoted to his inability to play the guitar. However, the only time we actually hear him play during the episode, he's upstaging Skwisgaar during a concert and doing a good enough job of it to threaten his confidence. The rest of the time, he's not as good as Skwisgaar and there is considerable distance between them in terms of skill, but he's still the world's second-fastest guitarist.
The general implication throughout the series seems to be that Toki plays the guitar entirely by instinct and muscle memory. If he actually is forced to THINK about it, say, by being handed some sheet music (which he cannot read) or by being called out on his skills by others, then he falls apart and can't play. He plays guitar by not thinking about playing guitar.
In an interview, Skwisgaar says that Toki was given the title Second-Fastest Guitarist as a booby prize after he was declared World's Fastest, though whether or not that's just Skwisgaar being a primadonna and an asshole is up for debate.
Brendon Small has said that Skwisgaar is supposed to represent the Yngwie Malmsteen-esque, blazing fast lead guitarist with perfect Baroque-inspired technique, while Toki is supposed to be the Iron Maiden-like, play-by-feel, sloppier blues-based player.
Professor Dementor from Kim Possible is said to be such a great villain that compared to him Dr. Drakken is even more of a joke. (Though at least Dementor invents his own doomsday devices.) But in the end he's foiled just as easily as Drakken, sometimes even more easily.
It's also possible that since Kim hasn't confronted Dementor nearly as often as she confronts Drakken, he can just claim he's a greater villain. Drakken can't, because Kim knows him much too well.
The Robotboy equivalent of Dr. Dementor is General Yakitori, who is supposed to be a greater villain than Big Bad Dr. Kamikazi. He won the "Evil Genius of the Year" award six times in a row, yet we've never seen him do much evil. Or much genius, for that matter.
Total Drama Island characters have tons of these since most characters don't get much screen time but their character bios reveal many abilities that the fans have yet to see in action, for example:
Ezekiel is apparently rather intelligent, since his bio mentions him speaking eight languages and winning the National Spelling Bee.
Cody and Lindsay are actually rich - this has never been mentioned within the show, although it explains why neither of them are that determined to win the prize money.
Gwen is said to love her family very deeply and apparently become "Soft as a marshmallow" around them, but she never mentions them, despite being away from her family far longer than most of the campers were.
Trent apparently loves motorbikes to such an extent that it even overshadows his love of music and spends almost all his time working on them. He never even says motorbike on-screen, though his love of music comes up often.
Inversion in Home Movies. Especially in the last season, everyone criticizes the main character's movies as being horrible, but they're actually pretty good, even by adult standards - and the characters doing them are pre-teens.
Parodied in Family Guy during the episode "Peterotica", where Peter writes pornographic novels. Everyone absolutely loves them, and they become a major hit, which would normally leave the audience wondering how Peter could possibly write anything halfway readable; however, the episode takes every possible opportunity to read excerpts from Peter's work, confirming that his writing is, in fact, downright abysmal.
Averted with Meg's singing. Mila Kunis is, by her own admission, a terrible singer, so Tara Strong took over when Meg actually had to sing.
Also, during the episode "420", after Brian succeeds in legalizing pot, he goes on a rant about how crime is almost nonexistent and productivity at work skyrocketed. However, all we see are people so stoned that they can't do their jobs properly. Perhaps the people gathering the statistics were too stoned to do their jobs properly, so they pulled the numbers out of their asses.
Raven from Teen Titans, the Emotionless Girl, was said to have to be emotionless to prevent her powers from going out of control. This was shown precisely twice, with most of the series showing her expressing varying degrees of emotion (and even falling in love in one episode) with no apparent problem. She did become a more developed character for it, albeit by ignoring the limitation instead of finding ways to work around it.
Ben 10 devoted two episodes to his future persona Ben 10,000, who was established as having obtained that many alien forms on the Omnitrix. Between the two episodes, he and his son use fewer than twenty of them total, and only three couldn't be found on Ben's watch in the present day. And that's ignoring thesequels...
Several of Ben's aliens are stated in their official profiles to have abilities that are never shown in the series, such as Wildmutt being able to fire spikes from his back (supposely Ben's form isn't mature enough, but we have seen many guys of Wildmutt's species who still couldn't do it), Jetray being able to breath underwater, and the list goes on. Ghostfreak's telekinesis was one in the first episodes, but Alien Force eventually had an episode with him using one.
Humongousaur's ability to grow bigger wasn't one in the original series, but became one in later episodes due to the writers apparently forgetting he could do that. Despite the fact it was his main power when he was first introduced.
Vilgax, when coming back in Alien Force, is stated to have absorbed the powers and equipments of 10 great heroes. He uses around five of them for all the time he had those powers.
In an episode of Rocko's Modern Life, Rocko and Heffer have to watch over Filburt's pet myna bird Turdy, whom he claims has a beautiful singing voice. We see no evidence of this throughout the episode, as all he does is squawk.
That was sort of the point. Filburt loved that bird, despite it being an obvious pest.
Played for laughs in Futurama, where the window wipers of the car from Knight Rider were the most evil window wipers in the world. It just didn't come up much in the show.
Wonderfully parodied with Zapp Brannigan. He is constantly praised as a brilliant military leader and a brave fighter but all the main characters know that he is in fact deeply stupid, cowardly and incompetent as well as being a major jerkass who takes credit for others' work.
Also played for laughs in The Simpsons episode, "Lisa's Wedding" where we meet Lisa's first love (or at least, first fiancée), in which Hibbert comments of Maggie, "She's quite a hellion but she does have an incredible voice." The closest thing she ever got to saying anything on screen was when Marge interrupted her when she spoke with her mouth full. (Or for that matter, immediately after Hibbert's quote, where said fiancée cuts her off when she's asked to sing.)
"Will that girl ever shut up?"
In another future episode, Maggie is revealed to be a world-famous singer. She still doesn't use her voice because she's pregnant and talking at that point could be bad for the baby, according to her doctor.
Further in The Simpsons Lisa Simpson is often referenced as a skeptic (mostly by herself however, so this could be construed as the character's obliviousness). However, the character is also shown to at various times show faith in Christianity, Buddhism, (temporarily) Wicca and alternative medicine, showing rather extensive compartmentalization. On the other hand, a Western Christian converting to 'fashionable religions' such as Buddhism and Wicca and preferring alternative medicine while looking down on her peers would be very fitting stereotypical behavior for a pseudo-intellectual character.
Winx Club, 4Kids dub: In one of the S1 episodes, Musa talks to two background students Ortensia and Priscilla about having to work together to save Alfea, letting drop that Ortensia has the best counterspell skills and that no one can fly as fast as Priscilla. Which would be nice for the final battle, except that, well, they're background characters. (In the original version, she only discusses how everyone has a part, without any abilities being mentioned.)
If we're mentioning Musa, might as well also let drop that in another S1 ep has Flora mention before an exam that Musa gets the best grades out of the Winx.note Her exact words differ slightly... Original: "Give us a break, we all know you're a straight A student." 4K: "I'm sure you'll be fine. You've got the best grades out of all of us." It's a break from the usual expectation of having the tech whiz be the straight A student, but not only do the writers never use this fact, at least one scene actually seems to be inconsistent with it (read main post, then 2nd reply).note The part with Musa attending Griselda's class. Incidentally, the 4Kids dub of the scene in question doesn't have this problem, as the dialog goes: "I competed in the All-Realm Magic Games. In fact, I was the first female black belt gold medalist." "And what year was that?" "It was 20 years ago, but I can still fight like a champion!" Point is, the writers have never done anything that would require Musa to really show off her smarts.
In the original, Flora also got top grades; when it was translated, Musa was the only one mentioned (which might be a little racist, since she seems to be the Magix equivalent of Asian).
One or two episodes have kids mention Stan's mom having large breasts. The way she's animated, she actually looks completely flat-chested most of the time.
Another episode has Butters make construction paper models of the main cast which, unsurprisingly, look exactly like them. Kyle then comments that they were slightly inaccurate, as his nose is shaped differently (neither he nor the model have a visible nose) and Stan's eyes are blue (each have black dots for pupils).
There are several other episodes where they play with this. In "The List," for example, Gerald says Kyle has his mother's nose; again, he has no visible nose, yet acts horrified since his mother's nose is somewhat large and ugly. "The Coon" would probably count as another example, merely because the characters can tell Mysterion's face apart from anybody else's while the audience can't.
Ugly Bob in "Terrance and Phillip in Not Without My Anus" apparently has a face which looks as if "somebody tried to put out a forest fire with a screwdriver" though he's animated to look like every other Canadian. A later episode makes it clear that Americans can't tell the difference, while other Canadians (and Saddam Hussein) can.
In Teenage Mutant Ninja Turtles, Shredder's ally Krang had a massive mobile fortress called the Technodrome, supposedly one of the most powerful weapons in the universe. It was largely reduced to McGuffin status, with occasional plots to recover it from wherever the hell it ended up after their previous attempt to get it to the surface of the Earth. Due to the short episodes, it typically took less than five minutes to be defeated the handful of times it actually got there; since "powering the Technodrome" was Shredder's default motive for doing anything, this was often five minutes after an entire series of trying to get it moving.
A running gag in King of the Hill is for characters to make note of Boomhauer's suave and charming way with words. This is never apparent to the viewers, as Boomhauer speaks in unintelligible mumbles.
In one episode he takes a heartbroken Bobby under his wing, and we see that Boomhauer's technique is the "shotgun approach" (put enough lead in the air and you're bound to hit something): he hits on every attractive woman he meets and gets rejected nine times out of ten, but he focuses on the one who says "yes" rather than the nine who say "no".
According to supplementary materials for Transformers Animated, Grimlock is equal in power to Megatron. While Megatron is portrayed as a huge Badass that can utterly thrash all five main Autobots at first, Grimlock is frequently tossed around by lesser opponents. There was actually going to be a scene in the first season finale where the two met face-to-face, and Megatron mopped the floor with Grimlock and the other Dinobots. (It ended up being cut due to bad animation and the realization Grimlock fans wouldn't like it.) Though power does not necessarily equate skill. Megatron is a several million year old war general in an army where Asskicking Equals Authority, while Grimlock has a very underdeveloped mind and is only a few months old.
In Generator Rex Providence's Red Shirt Army gets a whole episode about how each officer is put through Training from Hell in order to be top class officers to fight the EVOs that are infesting the world. Problem is the officers of Providence have largely been shown throughout the series as useless with in dealing with any EVO by themselves without the help of the superpowered Rex or Badass Normal Six.
To be fair, it's implied in that episode that on the fights big enough to need Rex they're really just there to provide a distraction with More Dakka so Rex and/or Six can do their thing. It's also implied that there are plenty of fights that weren't bad enough to need Rex (but since he's our protagonist we don't see those) where the Red Shirt Army does fine.
It's also lampshaded in-episode since Rex wonders how hard the training for the people who all he sees do is shoot stuff can really be so hard.
Col. Stinkmeaner on The Boondocks is an inversion: he's a blind man who can drive a car perfectly parallel to the road, detect objects in front of him (even while in the car), beat up Granddad and experiences no inconvenience as a result of his blindness, which Huey attributed to him having the Disability Superpower of radar-vision. Then he's revealed to not have any such ability; he just got lucky during his fight with Granddad who beats him in a rematch, accidentally killing him. and no credible explanation is given for how he could drive regularly without attracting any police attention. Unfortunately, he learns Kung-Fu in Hell and it turns out he hung out with a Badass Crew of Evil Old Folks.
The Redakai TV series seems to be relying on its website to give us our characterisation, one of which is that the character Zane, is the only one capable of defeating the hero Ky in straight combat. It hasn't happened yet and the character biography is so far the only indicator this could happen. The sheer amount of ignoring Show, Don't Tell in this show is just one of its many shortcomings.
Played for laughs on Adventure Time when Marceline's dad, the local Humanoid Abomination who rules a literal World of Chaos, states that the Ice King's pet penguin Gunter is the most evil creature he's ever encountered. Gunter is, of course, just a normal penguin, and it's even been implied that the Ice King can't tell his penguins apart and just calls whichever one's closest to him Gunter. Whatever the case, when Marceline's dad attempts to steal Gunter's soul, Gunter at least proves to not to be trifled with by countering with a slap.
Though the later episode "Reign of Gunters" features him as the main villain and has him pretty much conquer all of Ooo, so maybe Hunson was onto something.