- Acceptable Targets: 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.
- Accidental Innuendo:Yuck: You can't beat my pants! Thanks to Yin they're in a very naughty mood.
- Anvilicious: Mocked with The Lesson, a
villainhero who tries to hammer home aesops into people's heads (mostly Yang) with little success because even the people who agree with him (Yin) think he's an out-of-touch, overbearing jerk.
- Americans Hate Tingle: The show is universally despised in France, though nobody seems to know why.
- Awesome Music: The opening title card music is pretty impressive.
- Base-Breaking Character: Opinions on Coop is always one or the other, and never in-between. On one hand are those who think his antics make him awkward and endearing and want him to be Yin's love interest. On the other hand, there are those who despise him for being absolutely annoying because of his Stalker with a Crush tendencies during the first season and the fact that majority of the fanbase find Yuck to be a much better match for Yin than he will ever be.
- Die for Our Ship: Coop is hit by this to satisfy the ire of Yin x Yuck shippers.
- Ensemble Dark Horse: 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.
- Evil Is Sexy:
- 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:
- 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.
- Fan-Preferred Couple:
- Yang/Smoke is pretty popular too.
- Fanfic Fuel: 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?"
- Foe Yay: Many fans believe there is this between Yin and Yuck.
Yin: But, I thought you liked me.Yuck: Brett did (kicks robot head aside). But Brett isn't here anymore.Yin: (cue tears)
- In "Falling Yin Love", they even kiss each other and when Yin claims she "wants to be close to him" 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 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 Brett is revealed to be Yuck in disguise she seems heartbroken.
- "Funny Aneurysm" Moment: "Wonder Tweens Go!" has the cast of heroes sucked into "Super Titanic Mega Team Teen Tween," a parody of Teen Titans, where they end up losing frequently to Zarnot due to not taking their job as superheroes seriously in the slightest. Though it's a bit shallow, various elements of the parody strikingly resemble those featured in the extremely controversial Teen Titans Go! reboot.
- Hilarious in Hindsight: In one episode, Yin and Yang discuss how absurd it would be for a guy to get super powers after being bitten by a radioactive spider. A few years later, Disney would own that guy, and all of Marvel Comics.
- Ho Yay: Roger Jr's secret desire to be Yang's friend turns into this at times, especially in "Splitting Hares".
- Jerkass Dissonance: Yuck has quite the large fanbase despite the fact he's called a jerk almost constantly.
- Les Yay: Saranoia's obsession with Yin certainly leans into this, especially prominent in "The Truth Hurts".
- Moral Event Horizon: Ultimoose once he becomes the Nightmooster in "Deja Foo": he not only destroys the entire town but he kills Master Yo and Yin by burning them to death; to add insult to injury, he does it right in front of Yang.
- Popularity Polynomial: Not the show itself but the character Smoke has recently gained a large number of fanart (most of them NSFW-ish) on sites like Deviantart and Tumblr.
- Ron the Death Eater: Lina at times get's this treatment: although she's simply a Tsun Dere character with a 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.
- Self-Fanservice: Yin receives plenty of fanart depicting her as a well endowed teenage girl in skimpy or tight clothing; this mostly started to spring up after her Plot-Relevant Age-Up in one episode where she becomes an attractive teenager.
- Suspiciously Similar Song:
- Unintentionally Sympathetic: "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 Family-Unfriendly Deaths of his sister and mentor/father-figure, which 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.
- They Wasted a Perfectly Good Character: 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.
- The Woobie: The show has a handful of them
- Yuck in "Upstanding Yuck". All he wanted was to make friends with Yin and Yang and to prove he had became a good person. Throughout most of the episode, he suffers beatings from Yin and Yang without once getting mad at them. It's only until the end that he cracks and goes back to his evil ways. Still, you can't help but feel bad for him.
- Resident Butt-Monkey and Chew Toy Dave rarely if ever gets any respect from anyone, including his quote-unquote friends; although, opinion on him has changed after he discovered his power to control nature: bonus points for taking part in the battle during the series finale.
- Roger Jr. may be somewhat of an ass to the twins (and hell, to anyone, really), but deep down he admires Yang and only wants to be friends with him; it works, but that doesn't stop the latter from making a fool out of him at every other opportunity.
- Yin and Yang are also this in "The Confidence Game" where the majority of the episode has the two of them being horribly beaten by Eradicus and his Quirky Mini Boss Squad in a week long losing streak: they are at least 11 or 12 years old and their enemies are obviously older than them; also, the latter group seem to have an unsettling joy in beating the former.
- And then their master and father figure fakes his death in front of them to force them to fight for themselves.
YMMV / Yin Yang Yo!