History YMMV / Ben10

* SoOkayItsAverage: The franchise as a whole is usually seen as this by non-fans. While it has a lot going for it such as good fight choreography, creative aliens, and a lot of good talent (writers and voice actors alike), it also suffers from [[DependingOnTheWriter inconsistent writing]], fairly basic characterization, and rarely goes very far into worldbuilding the universe the characters live in, with a lot of it contradicted across the shows due to the different creative teams at the helm. Even some actual fans will admit that while they love the franchise, they do wish it had been more.
* TaintedByThePreview: [[https://www.youtube.com/watch?v=DffWEfarLxk The Comic-con preview clip of the reboot]] gained a large amount of flak on its reveal. Points of interest include Gwen and Grandpa Max having different voice actors, Diamondhead having different powers, the more simplistic designs, and the background characters having the same problem as in ''WesternAnimation/ThePowerpuffGirls2016''. [[note]]They look like they belong in a completely different cartoon, only here thanks to the trace amounts of {{Animesque}}, it's much more jarring. [[/note]]

* FandomRivalry: With the ''Anime/DragonBallZ'' fanbase, presumably mainly thanks to ''WebComic/FiveYearsLater'' and a notorious video by its creator in which he makes the fairly logic-backed argument that [[PhysicalGod Alien X]] could hypothetically [[FandomHeresy defeat Goku]].

* FriendlyFandoms: With the ''WesternAnimation/DannyPhantom'' fandom, with both shows being action shows about a KidHero with superpowers that aired around the same time.

* OneTruePairing: Ben/Gwen, due to a [[DidntThinkThisThrough perceived]] [[PlatonicWritingRomanticReading writing fumble]]. Gwen was originally planned to be one of Ben's classmates, but the writers found it difficult to justify having her tag along with him on his adventures. So they made her his cousin, except some thought the "damage" had already been done. Some viewers perceived their constant bickering as BelligerentSexualTension, and the slow-dance lesson scene didn't help. Not even officially pairing them off with other characters changed the shippers' minds.

* BaseBreakingCharacter: Gwen. Some fans love her, hate her, or switch feelings DependingOnTheWriter. Her fans praise her being a good {{Foil}} to Ben and her [[TookALevelInBadass eventually growing into a magic-based heroine of her own]], while her detractors perceive her snarky, aggressive behaviour toward Ben as her being a JerkAss and criticize the fact she is portrayed as better than Ben at practically everything and has never had any episodes where she goes through CharacterDevelopment unlike Ben.

* AlternativeCharacterInterpretation: A series specific example of the franchise-wide question of 'how sentient is the Omnitrix'. Did the Omnitrix unlock Cannonbolt just as the entity that destroyed Cannonbolt's homeworld was arriving to Earth, and Wildvine when Ben was confronted with an alien floral intelligence in the Mycelium, entirely by chance, or did something cause the two to be unlocked? Was it the Omnitrix itself, or the species genes itself? As WordOfGod would later state that Vilgax's own sample in the Omnitrix let him communicate with the Omnitrix wearer via dreams, the Omnitrix or the genetic samples themselves making the decision instead of random choice isn't implausible.

* DesignatedVillain: [[SubvertedTrope Subverted]] by Clancy in ''Side Effects''. He starts by just trying to defend his house, which was built by his grandfather, from being torn down by a councilwoman, and had no-one attempted to tear his house down, he probably would not have attacked those attempting to tear his house down, and just left them alone. But after the battle with the heroes gets started proper, [[JumpingOffTheSlipperySlope he attempts to kill everyone involved, then destroy the city with by sabotaging a nuclear reactor.]]

* AlternativeCharacterInterpretation: Was Z'Skayr/Ghostfreak always a psychopathic monster with Vilgax-level dreams of galactic conquest, or was he driven over the deep end by [[GoMadFromTheIsolation being trapped in the Omnitrix]] for an indefinite amount of time, and stranded on a planet with a sun that could burn him to ash? He makes it clear he ''hated'' being trapped("NO! I won't Go Back!" "Now, let's see how ''you'' like being trapped in someone else!") and his irrational grudge against Ben could be interpreted as him lashing out against the child who unwittingly held him prisoner and violated his autonomy whenever he went Ghostfreak.

* FanPreferredCouple: Go on any fan art site or shipping thread and you'll find that [[IncestYayShipping Ben/Gwen]] dominates those areas of the fandom.[[note]]The broader fanbase does not approve of this for very, very obvious reasons.[[/note]] Mainly due to their [[BelligerentSexualTension constant bickering]] and AwLookTheyReallyDoLoveEachOther moments, along with the fact that Gwen was originally planned to be one of Ben's classmates. The decision to officially pair them up with other characters in later series did ''nothing'' to deter the shippers. It's a common suspicion/theory among shippers that Gwen/Kevin and Ben/Julie were deliberate ShipSinking efforts on the part of the writers to discourage "Bwen".

* DesignatedVillain: Clancy in ''Side Effects'' was just trying to defend his house, which was built by his grandfather, from being torn down by a councilwoman, and had no-one attempted to tear his house down, he probably would not have attacked those attempting to tear his house down, and just left them alone.

* SelfFanservice: Gwen has a lot of fan art for a 10 year old. Some of it has her older than 10, while the bulk of it has her as a kid with [[BreastExpansion mature]] [[HartmanHips features]] and [[AgeInappropriateDress outfits that no child should be wearing]].

* WhatDoYouMeanItsForKids: The original series series made heavy use of BizarreAlienBiology to create characters with absolutely nightmarish designs, the sequels involved themes such as Nazi-esque attempts at genocide, powers with drug undertones and implied serial killers, and all four entries have at least one, if not multiple, cases of VileVillainSaccharineShow. By the time of Ultimate Alien, things had become so dark the writers decided to go LighterAndSofter in Omniverse in order to avoid making things too dark.

* BaseBreakingCharacter: Gwen. Some fans love her, hate her, or switch feelings DependingOnTheWriter. Her fans praise her being a good {{Foil}} to Ben and her [[TookALevelInBadass eventually growing into a magic-based heroine of her own]], while her detractors perceive her snarky, aggressive behaviour toward Ben as her being a JerkAss and criticize the fact [[PositiveDiscrimination she is portrayed as better than Ben at practically everything]] and has never had any episodes where she goes through CharacterDevelopment unlike Ben.

* OneTruePairing: Ben/Gwen, due to a [[DidntThinkThisThrough perceived]] [[RelationshipWritingFumble writing fumble]]. Gwen was originally planned to be one of Ben's classmates, but the writers found it difficult to justify having her tag along with him on his adventures. So they made her his cousin, except some thought the "damage" had already been done. Some viewers perceived their constant bickering as BelligerentSexualTension, and the slow-dance lesson scene didn't help. Not even officially pairing them off with other characters changed the shippers' minds.

* RelationshipWritingFumble: Ben and Gwen, which is an almost reverse case of the usual trope. The writers viewed them as just bickering, [[AwLookTheyReallyDoLoveEachOther if still loving]], cousins, and tried to write them as such. [[KissingCousins A few people took it differently.]] This actually created a PeripheryDemographic all by itself. Some older viewers initially hated the show, partially because of what they thought of as flat, immature, two-dimensional characters. [[IncestSubtext The instant they decided Ben and Gwen had crushes on each other]], the characters gained two or three levels of depth, skyrocketing it to the top of a lot of teen's lists.

* FanficFuel: Each alien in the Omnitrix belongs to an alien species with its own planet and culture, leaving ''huge'' possibilities to create various {{Original Character}}s. The Omnitrix is also stated to have at the very least 10,000 aliens (more than 1,000,000,000 after ''Alien Force''), meaning fans have a large gap available to imagine and create their own aliens.

* FanPreferredCouple: Go on any fan art site or shipping thread and you'll find that [[IncestYayShipping Ben/Gwen]] dominates those areas of the fandom.[[note]]The broader fanbase doesn't really approve of this ship though, as one will quickly find out by bringing it up in non-ship-centric sects of the fandom.[[/note]] Mainly due to their [[BelligerentSexualTension constant bickering]] and AwLookTheyReallyDoLoveEachOther moments, along with the fact that Gwen was originally planned to be one of Ben's classmates. The decision to officially pair them up with other characters in later series did ''nothing'' to deter the shippers. It's a common suspicion/theory among shippers that Gwen/Kevin and Ben/Julie were deliberate ShipSinking efforts on the part of the writers to discourage "Bwen".

* FanNickname: Eye-Guy’s species and homeworld name - Opticoid and Sightra - originally had ''zero'' canonical foundation whatsoever. The names were created by an anonymous user on the Ben 10 wiki in 2009, before another user created a page for it. It was given unofficial canon status in the ''Omniverser'' series bible in 2012 (which was then recovered in 2020). The names were simply made up as a joke and everybody just went along with it.

** In the show itself, Heatblast's continously flowing flaming hands look really cool.

* FoeYay: Ben and Kevin, who have [[ChainedHeat been chained to each other]] for an episode, and Gwen and Charmcaster, who [[FreakyFridayFlip spent a good part of one episode inside each other.]]

* SeasonalRot: Th fourth season is generally considered the weakest due to having less impressive episodes and overall story arc than the other seasons have.

* SelfFanservice: Gwen has a... DISTURBING amount of fan art for a 10 year old. Some of it, emphasis, SOME, has her older than 10, while the bulk of it has her as a kid with [[BreastExpansion mature]] [[HartmanHips features]] and [[AgeInappropriateDress outfits that no child should be wearing]].

* SelfFanservice: Gwen has a... [[{{Squick}} DISTURBING]] amount of fan art for a 10 year old. Some of it, emphasis, SOME, has her older than 10, while the bulk of it has her as a kid with [[BreastExpansion mature]] [[HartmanHips features]] and [[AgeInappropriateDress outfits that no child should be wearing]].

* SeasonalRot: The third season is generally considered the weakest due to having less impressive episodes and overall story arc than the other seasons have.

*** Gwen had been paired with [[WesternAnimation/TeenTitans2003 Raven]] since the original series, despite it being kinda weird with them having a different age on them, they never had crossover but this appeared on [[https://www.youtube.com/watch?v=ENU4GBISu34 old Cartoon Network promo]] featuring the two. Although this is not considered official and doesn't appear with the other promos.

*** In later years, Ben had started getting paired with Ami Mizuno, aka[[Franchise/SailorMoon Sailor Mercury]], in a sort of OppositesAttract manner. It's also meant to be humorous on a meta level, as [[Creator/YuriLowenthal Ben's teenage actor]] and [[Creator/KateHiggins Ami's English voice actor in the 2010's]] have also voiced [[Franchise/{{Naruto}} Sasuke and Sakura]] respectively.