History YMMV / CodenameKidsNextDoor

** L.I.C.E. has Numbuh 1 be asked what to do, to which he responds "Follow my lead – RUNNNNNNN!" Years later, Creator/BenDiskin would be voicing [[Anime/JojosBizarreAdventure another character]] (with a very similar voice even!) who was asked this question, and gave [[https://youtu.be/7GaJUmefY1I a very similar response]].

* [[HarsherInHindsight/CodenameKidsNextDoor Harsher In Hindsight]]

* [[TheyWastedAPerfectlyGoodCharacter/CodenameKidsNextDoor They Wasted A Perfectly Good Character]]

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* EnsembleDarkhorse:

** [[spoiler: Sector Z]] from ''WesternAnimation/OperationZERO'', who developed a huge fanbase despite only having five minutes of screentime.

* GeniusBonus: In "Operation F.A.S.T.-F.O.O.D.", the father shark complains about having to stop at a red light, saying, "Doesn't anyone realize I need to keep moving?" Biologically speaking, this is true--sharks need to be in constant motion, or else they die.

* TheScrappy: Lizzie Devine's first appearance where she's EasilyForgiven for attempting to brainwash Numbuh One didn't do wonders for her reputation among fans, and even after CharacterizationMarchesOn, it was a FandomSpecificPlot in even non-shipping fanfics to have Numbuh One dump her for the [[EnsembleDarkhorse better-liked Numbuh 362]].

** Despite learning that [[spoiler:Chad never betrayed the Kids Next Door]], Numbuh 1's thoughts on remaining a KND operative after turning 13 was never revealed. His hatred towards [[spoiler:Chad]] was so personal that he initially refused to believe [[spoiler:he was a FakeDefector the whole time]]. He never discussed about the Teens Next Door in the GrandFinale.

* EnsembleDarkhorse

* AlternativeCharacterInterpretation:
** Are The Little Traitor Dudes For Children's Defense, the "negative" counterparts of The Delightful Children From Down The Lane really good guys or just bad guys who were brainwashed like what happened with their counterparts?
** Given what we know now of [[spoiler: Sector Z and the true nature of the Delightful Children from Down the Lane]], was Lenny's attempt of a reverse mole ploy a sincere attempt to [[spoiler: break free of the brainwashing before the delightfulization returned]]? [[https://www.fanfiction.net/s/13238821/1/Strong This]] fanfic goes with this idea.
** Is the global organization a rebellious group of kids devoted to defying adult authority? Or a benevolent, somewhat KnightTemplar-ish group protecting the children of the world from those that wish to harm or unjustly oppress them? Although OP: Z.E.R.O. seems to confirm on the latter, some viewers tend to scale strictly on the former.
*** Or are they straight-up [[VillainProtagonist Villain Protagonists]] with a SympatheticPOV? Considering their rebellious and violent behaviours, this was a lot more plausible early on in the show.
** Is [[BigBad Father]] a psycho (with a convincing FreudianExcuse) suffering from VillainDecay, or a WoobieDestroyerOfWorlds?
** Does the KND inadvertently continue a CycleOfHatred by decommissioning operatives who turn 13? The older members of the KND would likely have no reason to arbitrarily turn on their friends and join up with the teens and adults who have been menacing them for most of their lives. But the KND rejecting them and trying to remove their memories could result in former operatives feeling betrayed so they devote themselves to destroying the organization and all it stands for. Those who are successfully decommissioned no longer have any type of loyalty or camaraderie for the KND and easily recruited by their former enemies because they don't know any better. "Operation: M.A.U.R.I.C.E." and Numbuh 12's betrayal seemingly supports this theory.
*** Building on this theory is Cree's behavior. While it's made painfully clear what side she's on, there are some hints that it might actually be because she crossed the DespairEventHorizon over growing older rather then just being a traitor. In "Operation: M.A.U.R.I.C.E.", when Abby bemoans the fact there's nothing she can do to escape growing up, Cree gets excited because she's been waiting for Abby to say that, hinting that she went through something similar and didn't have anyone to pull her out of it. Additionally, there are several hints throughout the series that Cree does genuinely want to make up with Abby, her own terms or not, but mishaps continue to happen that cause her to double down on her ideals.
** The entire show is a game a bunch of kids are playing, or a story they made up. (This theory seems to be gaining ground on 4chan)
*** And adding on to that theory, Numbuh One is a kid who possibly [[spoiler: moved away or died]]. Likely the former, because [[spoiler:Numbuh One eventually returns.]]
** [[spoiler:Knowing what we know now about Lizzie Devine/Numbuh Vine according to GKND, did she REALLY love Nigel or was this all just a ruse? On the same topic, it could be possible that every example of Lizzie being an idiot or oblivious to being in danger (like in Operation D.A.T.E.) shows she's been engaging in ObfuscatingStupidity the whole time. And also, was she being purposefully annoying towards him in the later half of the series as an attempt to make ''him'' break up with ''her'', but since that didn’t work, she ultimately had to end it between them in Operation G.I.R.L.F.R.I.E.N.D?]]
*** Rachel's reaction following Nigel and Lizzie's breakup. Was she merely feeling guilty for contributing to it or was it heartbreak caused by an apparent rejection towards her from Nigel's part?
** Jerry from BULLIES. While on the surface his story about wanting revenge on Numbuh 4 is sympathetic, we never really got Numbuh 4's side of the story either, just that "he deserved it". Was Jerry being entirely honest and Numbuh 4 just thought he deserved his permanent wedgie for being a nerd, or did Jerry do something to Numbuh 4 first and he refused to own up to it?

* HarsherInHindsight
** In "Operation: C.A.T.S.", Numbuh 5 claimed that she was a dog person. [[spoiler: Then came ''Operation: D.O.G.H.O.U.S.E.''... where she ended the honor roll student's curse of turning into homework-munching were-dogs, but not before [[ForcedTransformation becoming one herself]]]].
** At first, it was ok to not give sympathy to the Delightful Children From Down The Lane, but after the movie where we realized that [[spoiler:they used to be Sector Z, a missing KND sector and were "delightfulized", it would mean that their "negative" counterparts, The Little Traitor Dudes For Children's Defense were once evil operatives of the Destructively Nefarious Kids or DNK, a negative counterpart of the Kids Next Door where they are devoted to tormenting children everywhere rather than saving them.]]
** In Operation C.H.A.D., Mega Mom and Destructo Dad want to get rid of all members of the KND so that their son Numbuh 274 can become "Numbuh 1". While it would seem like an absurd and hilariously petty motive back then, it becomes a lot harder to watch come Operation T.R.E.A.T.Y. where it's revealed that Chad has developed a bitter InferioritySuperiorityComplex with Numbuh 1, one that destroyed the friendship the two had, [[spoiler: even in spite of Chad's betrayal of the KND being a ruse.]]
** The KND's Splinter Cell was an [[KnightTemplar extremist group]] who wants to get rid of adults bad AND good which the KND opposes. In Operation T.R.E.A.T.Y., the group are revealed at least and it turned out to be [[spoiler:fakes made by Numbuh 74.5239 and Numbuh Infinity who are aligned with the Galactic Kids Next Door who are above even Soopreme Leader Numbuh 362 that fight against adulthood in space]]. Just as we knew about the Splinter Cell comes the teaser for the next possible sequel series... [[spoiler:The G:KND has Nigel make the decision on activating something that would likely endanger the planet Earth in order to get rid of adulthood there once and for all which Chad begs him to not go through with it because of their friends and family still on the planet. To confirm Chad's fears, Numbuh Vine/Lizzie alerts Wally and Kuki to evacuate EVERYONE on Planet Earth, kid and adult alike! In a way, the Splinter Cell DOES exist and it is named the Galactic Kids Next Door who will take down adulthood even on the ''planetary scale''!]]
** Potentially, Lizzie in general. She's been Nigel's girlfriend for what might very well have been years, starting in Operation: L.I.Z.Z.I.E., and continuing up until their break-up in Operation: G.I.R.L.F.R.I.E.N.D., with her getting several episodes and even ADayInTheLimelight, with a bunch of CharacterDevelopment in between. [[spoiler: The G:KND "teaser" revealed her to be a Galactic-Level Operative, Numbuh Vine. In one fell swoop, [[WhamEpisode every single one of her appearances in the series just got put into question.]] It's no wonder [[TheCutie Numbah Three]] [[PrecisionFStrike dropped the F-bomb in shock.]]]]
** There have been reports of 'troubled teen camps' that are practically concentration camps for kids instead of Jews. If there is any reason for the KND to exist in real life, it [[http://www.cracked.com/personal-experiences-1680-5-things-i-learned-escaping-troubled-teens-facility.html is]] [[http://www.cracked.com/personal-experiences-1270-6-shocking-realities-secret-troubled-teen-industry.html this.]]
** Numbah 5's dad, who appeared in a few episodes, is a thinly-veiled {{Expy}} of Creator/BillCosby, right down to his jolly, somewhat absentminded rambling VerbalTic. As with many works referencing Bill Cosby, such appearances have a much darker tone following the real Bill Cosby's sexual assault allegations in 2014.
** "Operation: G.R.O.W.N.-U.P." has Father and a grown-up Numbuh One facing off, and, after Father comments on what a "disappointment" the DCFDTL are, Numbuh One responds with "that must run in the family". And then, in the same scene, Numbuh One says that "his Grandma can throw better than [Father]." [[spoiler:Which, considering Father is Nigel's uncle, and considering that it turns out Grandfather actually does find Father to be a disappointment... yeah.]]
** In the Kenny and the Chimp pilot, Kenny got... Swine Flu, a major epidemic in summer 2009.
** In 2003, "Operation: P.O.P." aired, where the "Soda Control Act" forbids anyone under the age of 13 from drinking soda, forcing kids to "brew" soda illegally and sell and drink it in speakeasies a la the days of Prohibition. In 2013, [[http://en.wikipedia.org/wiki/New_York_City_soft_drink_size_limit a law]] was almost passed in New York City that would have forbade anyone from purchasing/selling drinks with a certain sugar content in any size bigger than 16 ounces. One can only wonder what the Kids Next Door were up to during the months of battling over the law's legality.
** "Operation: T.R.I.C.Y.C.L.E." featured a character called Numbuh 10-Speed, a parody of Lance Armstrong. Not so funny anymore after the reveal that Armstrong used steroids to win his Tour de France titles. Lampshaded in the Galactic Kids Next Door ARG site, where entering Numbuh 10-Speed's name returns the response [[TakeThat "undergoing testing".]]
** "Operation: O.O.M.P.P.A.H.": In venting his frustration about being dragged along on this trip, Nigel says he wants to be with his friends and chastises Monty for doing all this because he read an article in the paper (essentially accusing him of needing someone else to tell him how to be a father). Monty sheepishly responds that he just wants to be friends with his son. This is played as a sad moment, but much later, it would get even worse, as we'd learn more about Monty's upbringing. He didn't have the kind of father who set a good example or wanted to be his friend.

* NauseaFuel
** Any episode where the children's teeth are emphasized on-screen, ''especially'' Knightbrace's first episode, "Operation: T.E.E.T.H.". Normally everyone has pearly white-teeth or at least slightly yellowed, but the instant the camera focuses in on them, you get a GrossUpCloseUp that show all sorts of gunk and decay in there, only dampened by the lack of further excess detail.
** One episode where "chicken pox" takes the form of literal squirming chicken heads sticking out of one's skin.
*** Plus, when the chickens themselves are in low quality, they look like writhing maggots in the kid's flesh.
** A villain named the Common Cold attacks by siphoning mucus out of his nose. [[SarcasmMode Especially lovely]] when he starts to ready a really big attack. Probably why he was DemotedToExtra after his first 2 appearances.
** In "Operation: P.I.N.K.E.Y.E.", being hit with a water balloon filled with pinkeye mucus would cause crusty red stuff to grow all over you. The episode's villain turns out to be using this crusty stuff as the crumbs in crumb cake. It gets even worse at the end of the episode: "So if the pinkeye was the crust, then what was the filling?" ([[spoiler:achoo!]]) Even worse? In ''two'' later episodes, Numbuh Two ''still eats the stuff'' and [[LampshadeHanging he comments about it]] as well!
** "Operation: V.I.R.U.S.", where there is a close-up of Cree's gigantic and disgusting pimple.
** A few of TheMovie's Senior Citizombies have ''sagging boobs.'' [[spoiler:This included the citizombified versions of Numbuh Three and Five.]]
** At the end of "Operation: C.A.K.E.D.-T.H.R.E.E., after the KND defeat the Delightful Children's Giant Birthday Present Robot with the help of an army of Chicks, Numbuh 1 is about to take the cake from the Delightful Children when the Chicks defecate all over it. Numbuh 1 then convinces the Delightful Children to eat the cake, which they do. It also counts as an in-universe example, as several children are grossed out from watching the Delightful Children eat the soiled cake on their television sets.
** Awesome music aside, "Operation F.O.O.D.F.I.T.E" grossed some people out, especially the giant slam-witch monster.
** At the beginning of Operation P.A.R.T.Y., Sector V (minus Numbuh 5) is looking over items that were taken from Cree's room. Numbuh 4 asks about a tube of pink stuff, and Numbuh 1 says that they think it's "some kind of unmeltable ice cream treat." Numbuh 4 then licks it, comments that the flavor is good.... and then Numbuh 5 smacks him with her hat and shouts, "THAT'S DEODORANT, FOOL!" One can't help but wonder whether or not it was actually used prior to being stolen. (Shudders)
** In "Operation: N.O. P.O.W.U.H," Sector V is force-fed all of Gramma Stuffum's disgusting food.

* TheyWastedAPerfectlyGoodCharacter:
** Many memorable villains like the Common Cold or Mega Mom and Destructo Dad were only the main antagonists for one episode. More jarring with the latter two that their son later became a villain and they were mostly relegated to brief cameos in episodes featuring other villains, with no interaction or acknowledgement of this fact.
** WordOfGod even acknowledges that it's a shame Numbuh 60 didn't get much development.
** Chad being a villain. Though he had a few episodes where he was the main villain, for the most part he was treated like just another teenager that the KND had to face. It was only in T.R.E.A.T.Y. (the ''final'' non-special episode) that any sort of interesting relationship between him and the KND, Numbuh 1 in particular, was explored.
** Two KND traitor agents who seemed to be important {{Arc Villain}}s never really reappear after their debut:
*** Numbuh 12 was never seen again after she betrayed the KND and joined the teenagers after realizing that since she was almost 13 and would be decommissioned soon otherwise. She could've become the ArchEnemy of Numbuh 86 like Cree is to Numbuh 5 and Chad to Numbuh 1.
*** Numbuh 206 completely vanishes from the series after escaping from his encounter with 86 in F.U.G.I.T.I.V.E. Season 6 planned to have him involved in some degree, but that didn't pan out for some reason.
** Sector Z had a memorable role in ''WesternAnimation/OperationZERO'' but after their big reveal [[spoiler:that they were the Delightful Children brainwashed all along]], the plot point is never revisited nor given any closure.
** "The Steve", the leader of the teenagers, only appeared in the second to last episode of the series.
** Maurice, aka Numbuh 9. He was introduced as something of a GoodCounterpart to Chad and introduced the major plot point to the series that [[spoiler: some of the elite operatives continued to work as deep agents for the KND, even after turning 13]]. After his introduction episode though, he more or less gets DemotedToExtra. [[spoiler:It doesn't help that the Teens Next Door as a whole drop off the face of the show altogether as if they never existed until Operation T.R.E.A.T.Y to (supposedly) explain Chad being TheMole at the last minute, making it look like an AssPull instead]].
** As amazing as Vin Moosk was in his only episode, some fans believe he could’ve been used at least once more. One of the very rare COMPETENT and GOOD adults? Alas, one appearance is all he got.

* DiagnosedByTheAudience: Numbuh 1's exceptionally paranoid and exhibits obsessive behavior, bordering on signs of mental illness.

** The Live-Action dramatization segment in Operation: C.L.U.E.S., featuring a huge grown man cosplaying as Mushi. To drive the point home, this same segment would be animated properly during a flashback sequence in Operation S.P.A.N.K.E.N.S.T.I.N.E., making the original Live-Action scene entirely pointless.

** The Live-Action dramatization segment in Operation: C.L.U.E.S., featuring a huge grown man cosplaying as Mushi.

* UnintentionallySympathetic:
** We're supposed to see Numbuh 4 as a brat in "Operation: H.U.G.S." for not wanting to be at a Rainbow Monkey amusement park. The thing is that Numbuh 3 knows fully well about his dislike of Rainbow Monkeys, yet she drags him against his will to the park, making her come off as selfish. And while it was rude and dumb of Numbuh 4 to make fun of the brand in front of the fans, he does it out of frustration over being taken to the park without having a say in it.
** Mushi to some. Yes, she did destroy her sister's Rainbow Monkey and wanted to keep it for herself, but getting grounded for life (and later on, longer than that) for that one misdeed comes off as KarmicOverkill.

** We're supposed to see Numbuh 4 as a brat in "Operation: H.U.G.S." for not wanting to be at a Rainbow Monkey amusement park. The thing is that Numbuh 3 knows fully well about his dislike of Rainbow Monkeys, yet he drags him against his will to the park, making her come off as selfish. And while it was rude and dumb of Numbuh 4 to make fun of the brand in front of the fans, he does it out of frustration over being taken to the park without having a say in it.
** Mushi to some. Yes, she did destroy her sister's Rainbow Monkey and wanted to keep it for herself, but getting grounded for life (and later on, longer than that) for that one misdeed may come off as DisproportionateRetribution more than LaserGuidedKarma.

* VillainWoobie: The Toiletinator. He's a bumbling mess of a villain, he doesn't get any respect, and the one time he made a friend, that friend turned out to be an enemy operative pretending to be an adult just to spy on them.

* UnintentionallySympathetic: We're supposed to see Numbuh 4 as a brat in "Operation: H.U.G.S." for not wanting to be at a Rainbow Monkey amusement park. The thing is that Numbuh 3 knows fully well about his dislike of Rainbow Monkeys, yet he drags him against his will to the park, making her come off as selfish. And while it was rude and dumb of Numbuh 4 to make fun of the brand in front of the fans, he does it out of frustration over being taken to the park without having a say in it.
* UnintentionallyUnsympathetic: In "Operation S.N.O.W.I.N.G.", we're supposed to feel bad for Lizzie when Jimmy forces a Boyfriend Helmet onto her. However, considering Lizzie did the same thing to Numbuh 1 and walked away a KarmaHoudini, many instead saw the moment as some ''long'' overdue karma towards her.

** Numbuh 86 is a StrawFeminist feared by pretty much every other KND operative out there due to her generally confrontational personality and position as Head of Decommissioning, but she's very popular and it isn't hard to find fanworks that focus on her.

** Numbuh 86 is a StrawFeminist feared by pretty much every other KND operative out there due to her generally confrontational personality and position as Head of Decommissioning, but she's also a definite fan favorite and it isn't hard to find fanworks that focus on her.
** The Toiletnator is never taken seriously by the KND and completely despised by his fellow villains due to his incompetence, ridiculous gimmick and LaughablyEvil tendencies, but he's equally beloved by fans. [[IneffectualSympatheticVillain for those same reasons.]]

** A few of TheMovie's Senior Citizombies have ''sagging'' ''GagBoobs.'' [[spoiler:This included the citizombified versions of Numbuh Three and Five.]]

* AudienceAlienatingPremise: The show was very successful, but many people were weirded by the series having a wacky premise that takes itself seriously. Remember, this is a series about a secret association of children fighting against a cabal of [[ChildHater child-hating adults]], where the classical things children hate (discipline, homework, veggies, etc.) are actual weapons against kids. The weird art style and the ContinuityLockOut didn't help much either.

** Numbuh 19th Century tends to get ignored or PutOnABus so people can pair Numbuh 86 with their favored character.

* TheScrappy: Lizzie Devine's first appearance where she's EasilyForgiven for attempting to brainwash Numbuh One didn't do wonders for her reputation among fans, and even after CharacterizationMarchesOn, it was a FandomSpecificPlot in even non-shipping fanfics to have Numbuh One dump her for the better-liked Numbuh 362.

** Numbuh 86 is a StrawFeminist feared by pretty much every other KND operative out there due to her generally confrontational personality and position as Head of Decommissioning, but she's also a definite fan favorite.
** The Toiletnator is never taken seriously by the KND and completely despised by his fellow villains due to his incompetence, ridiculous gimmick and LaughablyEvil tendencies, but he's equally beloved by fans [[IneffectualSympatheticVillain for those same reasons.]]

* JerksAreWorseThanVillains: The series has several villains, from [[BigBad Father]], to [[BigSisterBully Cree Lincoln]], all of which fans agree are too over the top to truly hate. This, in turn, makes two child characters far more disliked than any villain could be:
** Numbuh 1's girlfriend, Lizzie, who is rude not only to him, but almost every other character on the show. Not to mention, she is depicted as being rather abusive to Nigel as well, down to outright brainwashing him in a very painful process because he tried to save face when his friends started making fun of him. Not to mention, she has on more than one occasion, outright ''sabotaged'' the team because [[ItsAllAboutMe she wanted to put her own needs over all the other kids]]. Yet only once did she ever have to face consequences for what she did. Every other time she was EasilyForgiven.
** Numbuh 362's brother, Numbuh 363 is even ''more'' disliked, even with less appearances than Lizzie. The reason is simply because he is a BrattyHalfPint, who constantly talks down to Sector V and acts like everyone should be kissing his boots simply because he has a higher mission sucess rate than Sector V, even though it's implied to be moreso because of his teammates than him. It got to the point where several fans openly admitted that they were hoping Father killed him during the climax.

* TheScrappy: Lizzie Devine's first appearance where she's EasilyForgiven for attempting to brainwash Numbuh One didn't do wonders for her reputation among fans, and even after CharacterizationMarchesOn, it was a FandomSpecificPlot in even non-shipping fanfics to have Numbuh One dump her for the better-liked Numbuh 362.

** "Operation: C.A.K.E.D.-T.W.O." Unlike her debut episode, Nigel is angry at Lizzie for helping the DCFDTL just for cake and furiously calls her out of it.

** Chad being a villain. Though he had a few episodes where he was the main villain, for the most part he was treated like just another teenager that the KND had to face. It was only in T.R.E.A.T.Y. (the ''final'' non-special episode) that any sort of interesting relationship between him and the KND/Numbuh 1 was explored.

* MoralEventHorizon: Father trying to bake children into a cake. [[spoiler:He's revealed to have crossed it long ago when he transformed Sector Z into the Delightful Children permanently.]]

* ContinuityLockout: Start out early in the series and you can enjoy almost any episode, as most are standalone and StatusQuoIsGod. After the end of season one, however, plot points start wracking up, CharacterDevelopment gets well under way, and the series MythArc is ever-expanding and ever extensive. Not even halfway through the series, you'll start missing out on episodes that continue from previous parts of the story and numerous nods or references, and late series has character cameos, plot and characterization that all come together. This makes it BetterOnDVD to be able to watch the series in one go instead of all over the place, even if standalone episodes still exist almost up to the very end.