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 just like their counterparts?
Is the global organization a rebellious group of kids devoted to defying adult authority? or a benevolent, somewhat Knight Templar-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.
Crowning Music of Awesome: The rock opera episode, complete with a score by GWAR, who re-performed the song themselves after being unable to find stock copies. The episode was mostly Squick but the music was awesome.
Designated Villain: Done deliberately with Professor XXXL, who in all his appearances is just trying to create the perfect snowcone, but the KND always ruin his plans thinking he is doing something evil. Even Numbuh One knows his plan and goes along with it, and the kicker was he actually tried the perfect snow-cone before he was taken back by his friends.
Numbuh Three×Four were this in the first season thanks to fan reaction to "Operation: O.F.F.I.C.E.". The escalating Ship Tease in the subsequent seasons upgraded them into Official Couple status. Even the last episode revealed that they'd be husband and wife.
Numbuh 65.3×Lizzie: They're both glasses-wearing geeks. In "Operation: L.E.A.D.E.R.", Lizzie pretends to flirt with him and says she likes his pocket protector, making 65.3 blush. In "Operation: G.I.R.L.F.R.I.E.N.D.", 65.3 tells Nigel to say "hi" to Lizzie for him.
There's definitely some between Numbuh One and Chad Dickson, as well. "Operation: T.R.E.A.T.Y." is fodder for it with the Chained Heat situation and a flashback to Nigel and Chad's formerly close friendship. The entire situation reads like two exes being forced to work together after a bad breakup. The fact that Chad condescendingly calls him "Nigey" — his ex-girlfriend'sAffectionate Nickname for him — definitely doesn't help.
"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]." 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.
"Operation F.U.T.U.R.E." is a Terminator parody, where girly girls take over the world from an all girls school and the last rowdy boys are fighting a losing battle against them. Many academic studies show that in Real Life the girls are increasingly taking over, due to being generally better students and that today's rowdy boys are going to be tomorrow's losers.
Tiger Moms — the battle against adult tyranny is as important as ever!
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, 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.
Numbuh 5's father being a Bill Cosby expy, anyone?
Genius Bonus: 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.
Growing the Beard: The Season 1 Finale established continuity for the series, as well as the introduction of Father and the fact that the KND is not just the five featured on the show, but rather many different sectors.
In Kenny and the Chimp, one of the joke diseases that Kenny get is Swine Flu. And then in 2009, it came back (swine flu was around in the mid-1970s).
In "Operation: C.A.T.S.", Numbuh 5 claimed that she was a dog person. 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.
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 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.
The KND's Splinter Cell was an 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 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... 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!
Numbuh 5 and Cree's father Mr. Lincoln is a pretty obvious parody of Bill Cosby. It's much less charming in the wake of the sexual assault scandals that have potentially tarnished Mr. Cosby's family-friendly image.
Chad following the reveal that his betrayal of the KND was a ruse. On one hand, he's still an incredibly egotistical and bitter person, to the point that he tries to kill Nigel in Operation T.R.E.A.T.Y. However, it's easy to feel some degree of sympathy for him given the fact that he willingly sacrificed his own reputation and friendships within the KND; for the sake of his mission.
Memetic Badass: Just watch "Operation: K.N.O.T." and try to say Moosk doesn't have the makings of this.
Memetic Mutation: One fansite dedicated to re-captioning screenshots had characters discuss a clothing-optional resort. "The resort" has been a KND meme ever since.
"I hate everyone" Explanation Father's deadpan reaction to a space station crashing down on his house. Has become popular as a response to particularly annoying or infuriating posts or events.
One episode where "chicken pox" takes the form of literal squirming chicken heads sticking out of one's skin.
A villain named the Common Cold attacks by siphoning mucus out of his nose. Especially lovely when he starts to ready a really big attack. Probably why he was Demoted to Extra 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?" (achoo!)
Even worse? In two later episodes, Numbuh Two still eats the stuff and he comments about it as well!
Is no one going to mention "Operation: V.I.R.U.S.", where there is a close-up of Cree's gigantic and disgusting pimple?
The chickenpox episode; when the chickens themselves are in low quality, look like writhing maggots in the kid's flesh.
A few of The Movie's Senior Citizombies have saggingGag Boobs.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.
Rescued from the Scrappy Heap: Much of the hate towards Lizzie has died down both after "Op: GIRLFIREND" and the reveals in the GKND ARG that she was a secret galactic-level alien KND operative all along.
Seasonal Rot: Ironically around the time the series began to establish its mythos and continuity, which was about season 2 and onward for some people when Flanderization took hold of Numbuhs 3 and 4 despite all the character development everyone got, especially those two despite their Flanderization.
Ships That Pass in the Night: Numbuh 86 and Numbuh 60 is a rather popular ship, despite the fact that they never really had any onscreen interaction. (The closest was Operation: T.R.A.I.N.I.N.G., when Arctic Base got a distress signal from Moonbase. And even that turned out to be just Father disguised as Numbuh 86.)
Word of God 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.
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.
They Wasted a Perfectly Good Plot: The KND "Splinter Cell" arc foreshadowed an internal civil war in the KND between the extremist Splinter Cell that believes all adults must be destroyed vs. the more moderate faction that believes only the evil adults should be stopped. It is also revealed that the Splinter Cell had been kidnapping KND scientists for unknown reasons. However, near the end of the series, it turns out that the Splinter Cell is just an front for the KND scientists, who fake their kidnappings so they have more free time to watch their favorite science fiction shows as well as manage "the Galactic Kids Next Door", the workings of which were left very vague in the end. However, a teaser animatic featuring the original cast and produced by Mr. Warburton suggests that a civil war plot expanding upon the working of the GKND may be on the way. Still, many fans would've preferred this plot without the GKND.
There's also the matter of the 1/362 Ship Tease. Despite Operation: I.T. showing how close they were and Operation: G.I.R.L.F.R.I.E.N.D. all-but-confirming that Rachel has feeling for Nigel beyond friendship, it was never resolved. The trope comes in with after Lizzie dumped Nigel, which looked like it was foreshadowing that he would end up with Rachel. You can imagine how many fanfics have centered around them getting together.
Some fans were hoping that more would've came from Numbuh 1's report in "Operation: A.R.C.H.I.V.E.S.".
In the main team alone; 3+4 didn't so much have subtext as it was just plain text from the start, 2+5 was a slightly more debatable case, and 1+5 had some good chemistry. But let's not get into the web that the fans (and creators) have spun.
Villain Decay: Father started out as... well, pretty much Satan. Scary, always cloaked in darkness, and biblical in his wrath—and of course, his voice is Maurice LaMarche at his scenery-chewing best. Contrast this with the middle-aged dork he became later on.
Mega Mom and Destructo Dad were considered an extreme threat to the KND as a whole in their first appearance. It was also implied they took out the entire Kids Next Door (Not sure about Moonbase Operatives) with the exception of their son, Numbuh 274. Besides of the fact that often attend all of the Villain gatherings, their connection to Chad is never mentioned again, even after he becomes a Double Agent. Also, they are never seen using their powers in future appearances.
Woolseyism: All over the place in the Mexican Spanish dub, albeit not always for a good way, since all the characters speak using thick Mexico City accents, to the grade is very difficult not only for other Latin American viewers, but also for Mexican viewers outside Mexico City, to understand many dialogues without previous knowledge of the culture of Mexico City. The fact many of the voice actors are from Mexico City and also was dubbed there doesn't help.