The Fairly OddParents!, after being Un-Canceled several times, has suffered from Seasonal Rot harshly, so much so that it has its own page. In fact, the one-two punch of the final two seasons and The Fairly OddParents: Fairly Odder tarnished FOP's reputation to the point where most discussions surrounding it in the years afterward concerned its Seasonal Rot, its Franchise Original Sins, and little else. Eventually, with the departure of show creator Butch Hartman from Nickelodeon, the series was finally put out of its misery and cancelled for good. Nowadays, the thing that most fans look back on with this show is how much of an example it was of this trope; that it is often brought up as a cautionary tale for future series to be wary of, and unlike this situation with SpongeBob SquarePants (namely the show's time period during Stephen Hillenburg's departure from it following the first movie), how a sharp decline in quality can occur with a show and make it overstay its welcome even when its creator remains on board with it throughout its entire run.
Pre-Seasons 9 & 10:
- The general consensus is that Season 6 was the tipping point of the series for introducing Poof.
- To a minor degree, some feel the rot started in Season 5, or even as far back as Season 4 when Vicky changed from a bully of a babysitter to Satan in human form (though many agreed that the flanderization of Vicky began in Season 6) and for Season 2's infamous episode "Twistory", which was outright banned from the airwaves domestically.note
- Seasons 4 and 5 used to be considered this while it was still running due to the flanderization of a few characters, increasing reliance on mean-spirited humor, and occasional bad episodes, most notably as "It's A Wishful Life", a subverted and very cruel It's a Wonderful Plot where an unappreciated Timmy wishes he was never born and is shown a world where everyone's lives are better off without him. Now, they are widely considered to be a part of the show's "golden age" by many fans—except for "It's A Wishful Life", which remains the most despised episode of the show's golden age and one of the most despised in general to this day.
- While many claimed Poof's introduction was the show's turning point, believing that it relied too much on "whacky baby shenanigans" since then, Season 6 isn't even considered to be outwardly bad for the most part as it undid most of the Flanderization from Seasons 4 and 5 and Poof rarely got any episodes revolved around him and even if so, he was mostly in the background. As a result, several fans consider Poof's presence to be overanalyzed with literally nothing more than simply just plain blind hate and declare Season 6 to be the best season in the post-classic era and its quality on the same level as Season 5, to the point that Season 6 is sometimes lopped in with the classic era. The only exception is, as previously stated, the flanderization of Vicky as well as her younger sister, Tootie, who went from a nerdy yet nice girl who had a crush on Timmy despite her occasional stalking qualities to an overly obsessive, lovesick stalker who constantly harasses Timmy every chance she gets. Additionally, neither Vicky nor Tootie make appearances together since Season 6 despite the fact that they are sisters.
- Then came along Seasons 7 and 8, the actual start of the show's decline for many, where the writers began to slowly sideline most of the secondary characters, including Vicky, whose role as the main antagonist was passed on to Mr. Crocker, yet she still appears in the show's intro and outro sequences. According to series creator Butch Hartman himself, this was a deliberate decision as he and the writers favored Timmy's Dad, Mr. Crocker, and occasionally Foop instead. In Foop's case, after his debut in "Anti-Poof", his parents, Anti-Cosmo and Anti-Wanda, were written out of the show with the exception of "Balance of Flour", their last physical appearance in the series. In every episode featuring Foop after "Anti-Poof", neither Anti-Cosmo nor Anti-Wanda are anywhere to be seen. The Flanderization, along with continuity errors and inconsistencies, started popping up more around this time as well (such as "Lights Out" and "Timmy's Secret Wish!", with the former criticized for its overly mean-spirited tone and moral, even worse than that of Season 5's "It's A Wishful Life", and the latter for backstabbing on continuity and slower pacing filled with overuse of gags, especially considering it was otherwise a special supposedly meant to celebrate the show's 10th anniversary). It didn't help that Ray DeLaurentis, who had previously worked on other shows that weren't well-liked to begin with, became the series' story editor and a frequent writer at this time.
Seasons 9 & 10:
Seasons 9 and 10 are wildly considered to be the lowest point of the series.- Season 9 introduced Sparky, the new mascot for Timmy, who has been poorly received by fans. Besides Sparky himself, continuity was apparently abandoned by this point ("Let Sleeper Dogs Lie" being a particular offender due to retconning the events of "The Secret Origin of Denzel Crocker" from Season 3), and episode plots became extremely generic and unoriginal due to often rehashing older plots ("Desperate Without Housewives" being a particular offender due to reusing the plot of "Love Struck!" from Season 3, an episode that also wasn't well received to begin with) usually for the sake of shoehorning in Crocker and/or Timmy's Dad. The same trend continued well into Season 10. Additionally, while the new HD intro (with the animation redrawn and Poof added in) is passable, Vicky's headgags are all just reused versions of those found in Season 1, with the exception of the Sparky headgag.
- Season 10 introduced yet another new main character, Chloe Carmichael, as a replacement for Sparky and serving as a new neighbor for Timmy. She is even more hated than Sparky as many view her as an obnoxious and loudmouthed "little miss perfect" who makes Timmy even more of a loser and whom many feel doesn't meet the requirements for being miserable enough to deserve fairies. Her "perfect" traits are thankfully toned down in subsequent episodes, leading some fans to warm up to her. That said, she still remains a divisive character. While many fans were delighted to learn that Sparky would not be returning to the show, Season 10 still received its share of criticism.
- Almost every remaining character left in the show was flanderized over the course of the two seasons.
- Timmy was derailed from a mischievous, yet good-hearted child who just wanted his life to be better into a selfish and bratty jerk who only cares about getting what he wants. In Season 10's case, it was likely to make his status as Chloe's Foil more obvious to the viewers watching.
- Cosmo and Wanda took several levels in dumbass and were constantly rendered helpless and unable to help Timmy due to them losing their wands in practically every episode.
- Timmy's Dad went from a Bumbling Dad to a Lethally Stupid Manchild who causes destruction wherever he goes.
- Jorgen Von Strangle went from an intimidating and strict authority figure, who was either an enemy or an ally to Timmy and his fairies, to a Plot Device whenever the writers needed him to bend around the show's rules. The most notable offender was in "The Big Fairy Share Scare", the premiere of Season 10, where he forces Timmy to share Cosmo and Wanda with Chloe due to a "fairy shortage". Another notable offender is Season 7's "Temporary Fairy", which has him out of all fairies temporarily replacing Cosmo and Wanda, and the reason for this is because, as he states in the episode "all of the other fairies have godkids", (which is a total lie/plothole, since Binky Abdul, a recurring character that stopped appearing since Season 6's "Wishology", doesn't seem to have a fairy godchild, and he could have been Timmy's temporary fairy, which could have been a much more interesting concept for an episode, rather than just ripping off Season 2's "A Mile In My Shoe") and later shows that he serves no other purpose than to torture Timmy by making him do ridiculously dangerous activities (which is the exact opposite of what a fairy is supposed to do).
- Mr. Crocker went from a deranged teacher wishing to prove to the world that fairies exist into a carbon copy of both Cosmo and Timmy's Dad combined. Thus, he rarely has a Freak Out when he sees or otherwise senses something magical nor does he say "FAIRY GODPARENTS!" anymore. Notable episodes involving this (including Season 8 episodes) include:
- "Timmy's Secret Wish!", the aforementioned 10th anniversary special from Season 8, has Mr. Crocker helping Timmy return to Fairy World, only for him to be in the background for the remainder of the episode while concurrently making running gag jokes.
- "When Losers Attack", also an episode from Season 8, has him socially interacting with Foop in a rather positive and friendly manner, despite the latter being an anti-fairy, which is almost the same as the regular fairies. This is a perfectly missed opportunity for Mr. Crocker to hunt for the anti-fairies (and to a further extent, the Pixies) in general, which could have allowed for a more interesting, creative, and ambitious plot, and flesh out Crocker's character a whole a lot more rather than just simply continue being a typical villain wishing to destroy Timmy. The same can be said for Season 9's "Scary GodCouple", as well as Season 10's "Return of the L.O.S.E.R.S" (the sequel to "When Losers Attack"), "Clark Laser", and "Crockin' The House". While one could argue that both Crocker and Foop are evil and thus, have one enemy in common: Timmy, it does not overall excuse this plot hole for the aforementioned reasons.
- "Desperate Without Housewives", an episode from Season 9, has him appearing out of nowhere in Timmy's house, as he hangs out with Timmy, Cosmo, and Timmy's Dad after Timmy wishes for all women in the world to disappear for 24 hours.
- On the subject of Timmy's Dad and Mr. Crocker, they make an appearance in almost every episode, even in ones not directly focused on them, leading many fans to grow sick of them.note In Mr. Crocker's case, it only got worse when the episode "Chip Off The Old Crock" introduced his nephew Kevin Crocker, who is more or less a miniature version of himself.
- Poof's perplexing and inexplicable absence in most episodes in the second half of Season 9 (starting with "Let Sleeper Dogs Lie" onward) and all but one episode of Season 10. While Sparky being dropped from the show was confirmed by his voice actor, Poof is nowhere to be seen due to difficulties with having too many main characters in a plot. This is made all the more strange by the fact that Poof is still in the intro and outro sequences, and that Foop, Poof's Evil Counterpart, appeared in the season's very first episode and continued to make appearances throughout the season, even starring as the main villain in the episode "Blue Angel". Poof finally appeared in the episode "Certifiable Super Sitter", a rather insulting and terrible excuse for an episode celebrating the show's 15th anniversary, and is considered by many to be the worst episode in the entire show.
- The overuse of pop culture references, outdated memes, and 2010s slang in an attempt to pander to newer audiences. For example, in Season 10's "Return of the L.O.S.E.R.S", the Cosmo and Wanda subplot serves no other purpose than to bash the issues of the iPhone, which seems very out of place in a show like this one.
- While on the topic of the theme song, there was also the show's intro and theme song
being changed to reflect Season 10. Many feel that the new version of the theme song is inferior to the original due to having just two people singing instead of a full chorus and lazily pasting together clips from episodes of the season. At first, it seemed that the producers had caught on to the complaints and used the original intro in the episode "Girly Squirrely", but it only lasted for two episodes as from "The Fair Bears" onwards they began using the new intro once again. The lone good thing is that Vicky's headgags in the intro for this season were all different, some of which being original, in comparison to Season 9. - The sudden shift from the series' traditional use of hand-drawn animation to Flash animation in the last 13 segments due to their last-minute ordering from the network, thus, not giving the animators enough time to have it done hand-drawn or properly refine the digital animation. The show had been clearly hanging on loose threads at that point, but for many, this was the point where the show should have been put to rest—and eventually was. In 2017, the show was moved to Nicktoons, where it aired out its final episodes, with the last one airing in July of that year, followed by Butch Hartman leaving Nickelodeon several months later in February 2018note . On the week of April 2, 2018, Nick burned off most of the season 10 episodes that premiered on Nicktoonsnote , even if the episodes were placed at a timeslot shortly before their preschool shows.
