History YMMV / YinYangYo

* AmericansHateTingle: The show is universally despised in France, though nobody seems to know why.

* EvilIsCool: Ultimoose on his own is one of the most pathetic villains in the series. However, [[spoiler:in "Deja Foo" Ultimoose briefly gains the power of the Nightmaster and the results are both awesome and a bit terrifying. Not only does the "Nightmooster" destroy the town, but [[InvincableVillian he is so powerful that he effortlessly defeats Yin & Yo in a matter of seconds]], all while retaining his AwsomeEgo. In fact, the only way Yang was able to beat him was reversing time itself so he never got the power in the first place]]. Naturally, in every appearance afterward Ultimoose is back to his wimpy self, but it was fun while it lasted.

* FanficFuel: The show offers a plethora of these. But perhaps the most notable is the twins' mother, which was teased in one line of dialogue at the end of the series finale, "Yin Yang Who?"

* HeartwarmingInHindsight: Lots of moments across the show become sweeter after the finale revealed that [[spoiler:Yo is Yin & Yang's father]]. For example, way back in episode one when Yo is stroking Yin's head and comforting her when Yang briefly left to join Ultimoose's dojo.

* RonTheDeathEater: Lina at times gets this treatment: although she's simply a {{Tsundere}} character with a [[SassyBlackWoman sassy personality]], she's a generally nice girl and helps her friends in saving the world later; but to the fans, she is a selfish, uncaring bitch who wants Yang all to herself. Fanfictions often depict her as a terrible girlfriend, making sure that Yang's romance with the writer's character can occur with Lina out of the way.

* TheWoobie: The show has a handful of them.

* EvilIsSexy:
** Smoke and Saranoia, the only female villains that are the most attractively designed, have hourglass figures and are featured in plenty of fanart that emphasizes that:
*** Smoke wears a pretty short skirt that goes along with a SailorFuku.
*** One episode has Saranoia wearing fishnets stockings with a FrenchMaid outfit and another in a sexy pirate outfit.
** Ella Mental as well considering that both Master Yo and Yang found her plenty attractive even when they knew she was an evil minion to Eradicus.

* AcceptableTargets: Whoever worked on this show must've ''really'' hated old people, given how they're mocked one way or another in literally every episode that features them.

* FoeYayShipping: Yin and Yuck has more or less dominated the fandom's shipping realm from the events of "Falling Yin Love" alone. Not only do Yin and Yuck date, albeit with Yuck in disguise, but the two canonically share a FirstKiss-the only mouth to mouth one in the entire series runtime at that. But the real signifier of their being some genuine romantic feelings between the two of them is Yuck having nothing short of genuine enthusiasm on his face when Yin,[[spoiler: only trying drain his Woo Foo with the same gloves he used on her]], says how she "still wants to be close to him".
--> '''Yin:''' Oh Yuck, I don't care if it was all a trap. I still wanna be close to you.
--> '''Yuck:''' (completely dropping is defenses and leaning closer in anticipation) Y-You do?

* HilariousInHindsight: In one episode, Yin and Yang discuss how absurd it would be for a guy to [[ComicBook/SpiderMan get super powers after being bitten by a radioactive spider]]. A few years later, Creator/{{Disney}} would own that guy, and all of Creator/MarvelComics.

* UnintentionallySympathetic: "Welcome to the Dark Tomorrow" plays off Yang as being completely in the wrong for his role in the resurrection of Eradicus... completely skimming over the fact that he was ''manipulated'' into it by Eradicus' own minions posing as elder Woo Foo spirits with a mission to prevent the catastrophe. Not to mention that the supposed importance of their mission was hammered into Yang's head through the [[FamilyUnfriendlyDeath Family-Unfriendly Deaths]] of his sister and mentor/father-figure, which [[HarmfulToMinors he was forced to watch]], so while it was partially motivated by selfishness in wanting the glory of being a hero, he was also trying to save the lives of his family and friends.

*** And then their master and father figure [[spoiler:fakes his death in front of them to force them to fight for themselves.]]

* FanPreferredCouple:
** Yin/Yuck.
** Yang/Smoke is pretty popular too.
** [[IncestYayShipping Yin/Yang]].

* EarWorm: "YIN YANG YO! YIN YANG YO! YIN YANG YO!"

* SpotlightStealingSquad: Though he is undeniably a main character, some feel that Yang's CharacterDevelopment came at the cost of allowing his sister Yin to get an equal amount of screen time or her own individual character arc. Though both twins grow to be competent heroes and learn they work best as a team, it's Yang overgrowing his immaturity and selfishness that becomes a driving force for both seasons, dedicating quite a number of specials like "Deja-Foo" and "Welcome to The Dark Tomorrow" to him alone.

*** And then their master and father figure [[spoiler: fakes his death in front of them to force them to fight for themselves.]]

--> '''Yin:''' Oh Yuck, I don't care if it was all a trap. I still wanna be close to you?

* FoeYayShipping: Many fans believe there is this between Yin and Yuck.
** In "Falling Yin Love",[[spoiler: they even kiss each other]] and when Yin claims she "wants to be close to him" [[spoiler: only to drain his Woo Foo with the same gloves he used on her]] he looks pretty happy and smiles.
** There's also the fact that he always seems to be involving Yin in some way in his plans. This especially happens in "Falling Yin Love" but there's also "Camp Magic Pants" where he [[spoiler: devises for Yin to become evil by using her magic for wrong purposes so she can touch the golden pants statue and allow him to control it; even so, he jokingly thanks her.]]
** There seems to be some on Yin's side as well, especially considering her interest in bad boys. In "Falling Yin Love", after [[spoiler: Brett is revealed to be Yuck in disguise]] she seems heartbroken.
--> '''Yin:''' But, I thought you liked me.
--> '''Yuck:''' Brett did (kicks robot head aside). But Brett isn't here anymore.
--> '''Yin:''' (cue tears)

* EnsembleDarkhorse: Yuck - his overall screen time is three episodes per season and yet he's easily the most popular character, and all around most popular villain, to have come out of the series. He's also commonly shipped with Yin post the events of "Falling Yin Love" with fans exploring the high possibility he has genuine romantic feelings for her. This was further enhanced with "Upstanding Yuck" which reveals much of his HiddenDepths and a deep seated desire to be a better person which is [[NiceJobBreakingItHero sadly cut short by Yin and Yang's interference]] but completely certifies him as TheWoobie.

* JerkassDissonance: Yuck has quite the large fanbase despite the fact he's called a jerk almost constantly.

* EnsembleDarkhorse: Yuck - he's proven more than once that he's an unfeeling jerk and a borderline sadist, yet most fans tend to find him to be the most interesting.

* FoeYay: Many fans believe there is this between Yin and Yuck.

* TheyWastedAPerfectlyGoodCharacter: Ever since the first episode he appeared in, fans instantly loved Yuck to the point they wanted him to be a part of the main cast or at least be involved in far more episodes; though he isn't entirely wasted, out of the fairly lengthy seasons, he only appears in six total.
* TheWoobie: The show has a handful of them

* EnsembleDarkhorse: Yuck - he's proven more than once that he's an unfeeling jerk and a borderline sadist yet most fans tend to find him to be the most interesting.
* EvilIsCool: Ultimoose on his own is one of the most pathetic villains in the series. However, [[spoiler:in "Deja Foo" Ultimoose briefly gains the power of the Nightmaster and the result are both awesome and a bit terrifying. Not only does the "Nightmooster" destroy the town, but [[InvincableVillian he is so powerful that he effortlessly defeats Yin & Yo in a matter of seconds]], all while retaining his AwsomeEgo. In fact, the only way Yang was able to beat him was reversing time itself so he got the power in the first place]]. Naturally, in every appearance afterward Ultimoose is back to his wimpy self, but it was fun while it lasted.