History YMMV / OnePunchMan

* ArchivePanic: With how many redraws happened in the Monster Association Arc, it's hard to keep a track on which version is official and which is not. The new versions of chapters often don't get translated to other chapters either, which just adds more oil to the fire. The Wiki itself has this problem, as the online chapters differ from volume ones, so many of the latter don't even have their own pages.

* MisaimedFandom: Due to its very premise, the series attracts lots of attention from "power-scaling" fans who like to debate about who can beat who based on feats, similar to ''Dragon Ball''. This is terribly ironic, as a major theme in the story is that logic can't capture certain forces of nature; the flaws of the hero rankings and monster disaster levels are a clear example. Not only is Saitama's strength incalculable, but everyone's is - characters are constantly overestimated or underestimated by those around them, many fluctuating greatly in strengths and weaknesses across the series. It's like the story ''itself'' is making fun of such calculations.

* MisaimedFandom: Due to its very premise, the series attracts lots of attention from "power-scaling" fans who like to debate about who can beat who based on feats, similar to ''Dragon Ball''. This is terrible ironic, as a major theme in the story is that logic can't capture certain forces of nature; the flaws of the hero rankings and monster disaster levels are a clear example. Not only is Saitama's strength incalculable, but everyone's is - characters are constantly overestimated or underestimated by those around them, many fluctuating greatly in strengths and weaknesses across the series. It's like the story ''itself'' is making fun of such calculations.

* MisaimedFandom: The series has attracted lots of attention from "power-scaling" fans who like to debate who can beat who, similar to ''Dragon Ball''. This is due to Saitama often being touted as the most powerful character in all of anime or even all of fiction. It's ironic really; a major theme throughout the series is that logic just can't capture certain forces of nature. Saitama's strength is incalculable, with no one being strong enough to stand up against him to fully measure it, and due to his explanation of becoming that strong being a simple training regime, people are only limited to making hypotheses about how he became that strong, such as Dr. Genus' "breaking the limit" theory. "Can Goku beat Saitama?" No. No one can. Not even Saitama can. It's not fair, and it's not supposed to be. It doesn't make sense, and that's on purpose.

* MisaimedFandom: The series has attracted lots of fans who like to argue about power levels and who can beat who, similar to ''Dragon Ball''. This is due to Saitama often being touted as the most powerful character in all of anime or even all of fiction. It's ironic really; a major theme throughout the series is that logic just can't capture certain forces of nature. Saitama's strength is incalculable, with no one being strong enough to stand up against him to fully measure it, and due to his explanation of becoming that strong being a simple training regime, people are only limited to making hypotheses about how he became that strong, such as Dr. Genus' "breaking the limit" theory. "Can Goku beat Saitama?" No. No one can. Not even Saitama can. It's not fair, and it's not supposed to be. It doesn't make sense, and that's on purpose.

** A rare example of Viewer Race Confusion is present with Superalloy Darkshine. He has many of the characteristics of a stereotypical African man, but in a flashback, he is shown to be lighter-skinned; in reality, he just has so much bronzing and spray tan on that he appears black, referencing a real-life UsefulNotes/{{bodybuilding}} practice.

* WinBackTheCrowd: While the return of Creator/JCStaff left fans feeling mixed, people were still impressed by the quality of what was shown in the official trailer for the upcoming 3rd season, showcasing that the long wait for any news was worth it.

* SeasonalRot:

* AntiClimaxBoss: Gouketsu gets a ''lot'' of build-up in the Super Fight Arc. He beats Genos, martial arts champion Suiryu and a monsterized Bakuzan without even trying. Genos, one of the few people who knows Saitama's real strength, says he sensed an unfathomable amount of power from Gouketsu in their short fight, similar to Saitama, and believes only a quick ambush by Saitama ''and'' the S-Class heroes could safely defeat him. When Saitama goes to face him alone, Suiryu begs him not to go, and when Saitama leaves, Suriyu curses himself for not being able to stop his savior from meeting certain death. [[spoiler: And then Saitama casually obliterates Gouketsu (off-screen no less), just like nearly every opponent he faces. When asked if he was strong, Saitama says he couldn't tell, because Gouketsu didn't last long enough to make an impression.]]

* AwesomeEgo: Garou is this way for most of the Human Monster Saga as he continuously beats hero after hero; fans just love his unrepentant evil. [[spoiler: Until Saitama brutally humbles him.]]

** After [[MemeticLoser becoming a meme for never winning a fight]] and usually ending up in pieces as a set-up for stronger heroes, Genos [[ThrowTheDogABone gets some vindication]] once he joins the fight against the monster association. Not only does he [[TookALevelInBadass showcase his improvements]] by swiftly eliminating G5, he then becomes an active player in the battle against [[spoiler: Psychos/Orochi]] and instrumental for the victory and finishing a major fight while still standing.

** Garou has a sizeable fanbase for his cool fight scenes and AntiVillain tendencies. [[spoiler: Ironic, considering how bad he is at being evil as Saitama points out]].
** Lord Boros can also qualify thanks to his unique design and transformations as well as his massive ship. It certainly doesn't hurt that he's the first villain to [[VillainRespect treat Saitama with respect]] and [[spoiler: [[NoSell doesn't go down after just one punch!]]]]

** [[spoiler: Psykos and Orochi's fused form has been nicknamed "Psykorochi", or some variations of it like "Psyrochi".]]

** Garou's [[spoiler: horned monster form was named "Awakened Garou"]] by the fans, but has yet to be officially referred to as such.

** While started out as a meme, eventually some fans believe that [[spoiler: King]] does have superpower on his own, with the most common one being his extreme luck to [[ActionSurvivor survive even the most dangerous situations]], [[DoesNotKnowHisOwnStrength even if he isn't aware of it]]. Considering that the setting is a CrapsackWorld where [[AMillionIsAStatistic normal humans can die easily in large number without any fanfare]], there's no way [[spoiler: King]] can survive disasters after disasters without any innate superpower if he's just a regular man, which makes this theory rather believable.

* HesJustHiding: Mosquito Girl, [[ATwinkleInTheSky having merely been sent flying]] by Saitama's swat, when the monsters he hits usually end up in LudicrousGibs (even the bloody smear she leaves on a building in the anime can be explained away as the result of her blood sack rupturing on impact). It doesn't hurt that Murata has published [[https://pbs.twimg.com/media/Ce7aWy1VAAA6LDV.jpg:large drawings of her as a worker in Genus' takoyaki stand]], complete with prosthetic limbs and a bandage above her buttocks, where her abdomen used to be.[[spoiler: Eventually she came back in chapter 190.]]

** Many fans guessed that Sweet Mask [[spoiler: is an Ugmon monster himself]] before the reveal.
** It was widely theorized that Orochi [[spoiler: would return after his fight with Saitama]], which he did twenty chapters later.
** When [[spoiler: Golden Sperm showed up very early into the Monster Association battle compared to his webcomic counterpart]], fans were quick to guess an even stronger form would be revealed later on. This came true with [[spoiler: Platinum Sperm]].

** Tatsumaki, [[spoiler: who was taken from her family at a young age and used as a guinea pig for years because of her psychic powers. She was even isolated from the outside and denied any contact with her parents or sister. Eventually she stopped using her powers out of spite, but it only led to her being thrown in a cell until she started using them again. Even when an experimental creature went on a rampage, Tatsumaki still didn't use them and was only saved by Blast stepping in to kill the monster, after which he told her not to expect someone to come save her every time. It led to Tatsumaki's current worldview, being bitter at the world and believing that she can only rely on herself and that connection to others and coexistence are pointless. It also led to her being overprotective of Fubuki which of course has led to their strained relationship, Tatsumaki being a meddlesome, stifling control freak in Fubuki's life who thinks she knows what's best for Fubuki. All in all, Tatsumaki is a giant bag of issues due to severely traumatic experiences as a child which could have been avoided if someone had shown her basic decency.]]

** Garou. He was bullied by the other kids in school for sympathizing with the monsters on TV shows and for not playing along with their hero games on the playground. When school authorities got involved, he was [[UsefulNotes/VictimBlaming victim-blamed]] for not conforming to the other kids' standards. Because of this, he's always felt like a universally-hated underdog, and it's part of why he goes on his self-destructive crusade to knock heroes down a peg and become the ultimate monster. And despite all of his violence, he never truly intends to kill anyone -- he just wants to give the little guys of the world a chance to get back at their oppressors. Then, it's revealed that [[spoiler: Garou wants to become the ultimate monster so that ''someone else'' can become the ultimate hero in return -- the poor guy wants good in the world, but simply lacks the self-confidence to be a hero himself]]. Makes it hard not to root for him, or at least get him a hug.
* JerksAreWorseThanVillains: The villains of the series usually lean into EvilIsCool (Garou, Boros, Phoenix Man), EvilIsHammy (Carnage Kabuto, Deep Sea King), or sexy (Mosquito Girl, [[spoiler: Psykos]]) territories, sometimes combiniation of all these three (Speed-o'-Sound Sonic) or straight up [[WeHardlyKnewYe don't last long enough to give any impression]] (Vaccine Man, Beefcake) usually thanks to Saitama himself. However, there are several loathsome characters on the heroes and citizen sides who are straight up unlikeable, even more than the villains.

** King. After all, he's the strongest man in the world. [[spoiler: Even after he's revealed to have no superpowers at all, this only elevates his badass status to many, such as his extreme luck to [[ActionSurvivor survive even the most dangerous situations]], or the ability to summon Saitama anywhere and anytime.]]

** Garou, after [[CurbStompBattle curb-stomping]] [[spoiler: nearly every S-Class hero]].
** Phoenix Man, for his [[spoiler: sudden power boost that rivals even the ''Monster Association cadres'']]. Murata has also redrawn Phoenix Man's fight with [[spoiler:Child Emperor]] multiple times, leading to jokes that Phoenix Man's [[spoiler: resurrection]] powers traverse time and space. He even [[{{Rewrite}} brought the Narinki Squad back to life]].

* ShockingMoments: The series as a whole is full of this, from Saitama punching Vaccine Man in one hit, to [[spoiler: punching a meteor, fighting an alien leader who can destroy worlds, (and who kicked Saitama to the moon!!!) an enemy who can defeat nearly all S-Class heroes, and finally fighting Tatsumaki herself.]]

** Saitama's encounter with Boros, [[spoiler: particularly Saitama's deadpan response [[https://40.media.tumblr.com/99f93f96332bdc206f7b92b300844b4f/tumblr_inline_nyx0y4YAsm1r5ight_540.png when the latter loses his armor]].]] This includes [[https://www.youtube.com/watch?v=_Eqpc7E5tu4 Serious Series -- Serious Punch!]], being an amazing way to finish off the first season.

* TheyWastedAPerfectlyGoodPlot: Some fans feel that specific chapters before being retconned were better that the official, "canon" version. [[spoiler: In one of the chapters, before it got changed, Saitama stops his fight with Awakened Garou, saying that it won't get them anywhere. They proceed to sit down in a near apartament. Even those who are satisfied with the change say the version before would be quite interesting to read.]]

** Boros is quite popular with the fans for the following reasons: He's the first one to somewhat match Saitama in a fight; his BloodKnight and AffablyEvil personality is likeable; he [[GracefulLoser accepts]] his demise [[GoOutWithASmile peacefully]], and is actually quite [[EvilIsSexy an attractive villain]], despite -- or maybe even because of -- him having [[{{Cyclops}} only one eye.]] He is also one of the few villains that respect Saitama. It's not uncommon to find fanart of him and Saitama together.

* JerksAreWorseThanVillains: The villains of the series usually lean into EvilIsCool (Garou, Boros, Phoenix Man), EvilIsHammy (Carnage Kabuto, Deep Sea King), EvilIsSexy (Mosquito Girl, [[spoiler: Psykos]]) territories, sometimes combiniation of all these three (Speed-o'-Sound Sonic) or straight up [[WeHardlyKnewYe don't last long enough to give any impression]] (Vaccine Man, Beefcake) usually thanks to Saitama himself. However, there are several loathsome characters on the heroes and citizen sides who are straight up unlikeable, even more than the villains.