One caused by dub changes. When he smiled and shook his head, did Jiànliáng/Henry forgive his father for causing the Tamers' digimon to need to return to the Digital world or not? In the original Japanese, Zhènyǔ admits to his son that what he did was unforgivable, and looks down in shame, however, in the English dub, Zhènyǔ just tells his son that things will get better.
Is ADR-01 (AKA J-Reaper) like the rest of the D-Reaper's agents, a mere puppet following the singular will of the program's directive of observe and destroy, or has it achieved some degree of independent sentience? Or is it perhaps somewhere inbetween?
While Tamers is held in high regard in United States, opinions towards it in Spain (a country where the Digimon franchise used to be a juggernaut) tend to be very polarized. However, Takato is unambiguously counted as one of the least liked human characters in the franchise, with Spaniards putting him under any of his cast mates and even leads from less successful seasons (like Davis or Takuya).
While the method for defeating the D-Reaper can come off as this since the show seemed more interested in building up how invincible it was than finding a way to defeat it, nothing compares with the Cruel Twist Ending where it turns out the Digimon can't remain in the real world, something that was never foreshadowed earlier in the series.
Ryo being able to matrix evolve with Cyberdramon just happens and has no explanation.
Takato is incredibly divisive, especially when compared to Tai and other "goggle boys" of the franchise. Views of him range from a more realistic and freshly different main character to a Wangst-ridden crybaby who doesn't deserve the leader status. The last note is telling, as there's a surprising amount of people who believe that making either Rika or Henry the series's central protagonist would have made it much more interesting.
Even although what is said above, Rika and Henry are also subject to different opinions. In the first case, she is often liked for being a strong female character and having more personality than her homologues from other Digimon series, while others dislike her for trying too hard to fit the archetype and being unreasonably jerkass to other characters. As for Henry, while some praise his calmheadness and intellectual approach to his problems, others feel his internal doubts are too near Wangst field and thus he is not different enough from Takato to make a good Lancer to him.
Alice - some feel that her brief moment was powerful, but others feel that her complete lack of foreshadowing makes her and Dobermon come off as a Plot Device - others forgive her because there was a Dub-Induced Plot Hole.
There are two kinds of Digimon fans. The fans that love this season the best for being Darker and Edgier and overall more mature than Digimon Adventure and Zero Two, with a focus on Character Development and psychological realism over constant monster-of-the-week action, and fans that hated this series for taking too many elements and plot points from Adventure, sometimes feeling like a re-thread, and for taking place in another universe, thus completely dropping the characters they have come to love over the course of two years.
There is debate about whether Tamers should stand out as a deconstruction of the Mons genre in comparison to the rest of the Digimon franchise. Detractors usually point out that everything that makes Tamers gain said label (death presented as dramatic, battles with traumatic consequences, mons losing control horrifyingly, loved ones threatened for real, angst, alienation) was already present in Adventure, and some even believe that vital plot points like the leader's Digimon going berserk (Skullgreymon/Megidramon) or a character dear to him being kidnapped (Kari/Jeri) were actually better played back in the first series. On the other hand, defenders often counter by arguing that Tamers is deeper and more mature in its deconstruction, that its more-realistic presentation increases the impact of these darker notes, and that it does a better job at exploring its psychological themes overall.
Whether Runaway Locomon and/or Message in a Packet are canon. Well, not so much which is "canon" so much as whether to accept Message in a Packet banishing Runaway Locomon to Canon Discontinuity or to subject Message to Fanon Discontinuity in favor of Runaway.
Death of the Author: Konaka in his notes indicates that Rika's lack of a father has not much of anything to do with her character and arc. A great many fans, notably including a certain JesuOtaku, call bullshit.
Do Not Do This Cool Thing: Sort of an inversion. Even in the final act where all has gone to hell and Juri is being agonizingly tortured, each next episode preview ends with the phrase "you, too, should aim to be a tamer!". "Doing this horrifying thing, you mean?"
Ensemble Dark Horse: Alice, who only appears for one episode and only as a plot device, but her mysterious character and wonderful voice acting sold her to the fans.
Epileptic Trees: There's a Casting Gag with the teacher Miss Asaji being voiced by Lara Jill Miller, who also voiced Kari in the first two seasons and in the epilogue of 02 grew up to be a teacher herself. This combined with the fact that she does resemble a grown-up Kari led many young viewers to come up with theories about how she was secretly Kari, who somehow jumped from her dimension to this one.
Ruki is more commonly paired with co-stars Takato and Jianliang by the fandom than she is with Ryo; which one of her best friends she ends up with generally tends to be determined by which side of the Pacific you're on. The Japanese tend to enjoy pairing her off with Jianliang, while westerners prefer her with Takato.
For the actual digimon themselves, people are very fond of Impmon/Renamon, thanks to the chemistry and Ship Tease that came with their Odd Friendship. Some people even ship their mega forms together.
Another fairly popular pairing is Guilmon/Renamon, and much like the aforementioned Impmon/Renamon, also shares some Ship Tease moments also thanks to their Odd Friendship and Worthy Opponent views on each other. Also helps that Renamon was the first Digimon Guilmon meets (before and after he was created), and she somehow sensed him watching her. Some people even ship their ultimate forms together.
Fanfic Fuel: Amusingly, Rukato fans have produced a great number of fanfics that involve an Alternate Ending to "Runaway Digimon Express", where Renamon doesn't come between Takato and Ruki at the end of the movie.
Fanon: Ai and Makoto are not twins (Ai is clearly older than Makoto), but good luck finding a different reference to them in fanworks.
As mentioned elsewhere, the CD drama which retconned the second movie. The fans, however, gleefully ignore it, or try to connect them anyway.
The audio drama released in 2018 with the Blu-Ray boxset, which reveals that Jenrya became a researcher, Ruki became a motorcycle stuntwoman, and that the kids still haven't reunited with their Digimon after nearly twenty years.... then again the Drama makes use of time travel so is canonicity is heavily debatable.
Faux Symbolism: Dukemon Crimson Mode has an attack named Quo Vadisnote Latin: Where are you going?. The phrase refers to a Christian tradition depicting Peter and Christ meeting on the road; Peter asks "Quo Vadis" and Christ responds that He is going to Rome to be crucified again. Dukemon CM's attack basically vaporizes a city's worth of enemies at once. You find the connection!
Germans Love David Hasselhoff: Tamers is such an almost Cult Classic among fans from the Anglosphere that it might be shocking for those to learn the series did not do especially well in Japan or any other country. One of the reasons behind this, aside from the typically polarizing Continuity Reboot, is that Chiaki Konaka and his works are actually very niche in his native country and tend to do much better abroad, particularly in United States. Reception in Japan and other countries has improved with the years, in no small part due to the influence of the American fandom in the internet, but it is still tepid in comparison.
Televisions and computers use the same Chromatic Arrangement. In 2010, Sharp added yellow into that protocol as a fourth color when they rolled out their Aquos Quattron LCD TV.
Juri chased Leomon around the park passionately, claiming that it's their destiny to become partners, much to Leomon's horror and confusion. Watch as they do become partners, and Leomon does a complete 180 on his view of her.
The final enemy the heroes face is a rogue program that takes the form of a red Blob Monster. It was sealed away in the backstory and, now that it's free, intends to assimilate other things into itself and grow more powerful as a result. To this end, it creates agents to act as its proxy by breaking and mutating parts of itself. ''Megaman Battle Network 3'', which would be released one year after the anime concluded, would feature an extremely similar antagonist in the form of Alpha.
Iron Woobie: Ryo. That back story alluded to under All There in the Manual? It's not a happy one. Aside from his reluctance to really bond with others, you'd never guess.
It Was His Sled: Impmon is Beelzemon and the true Big Bad is a computer program called the D-Reaper. Oh, and Leomon dies. The first two in particular were surprising at the time, but nowadays even people who haven't seen the show know them.
Like You Would Really Do It: The first episode ends with the "cliffhanger" on if the main character will be annihilated by his own partner. It's not that kind of show... yet.
Memetic Molester: IceDevimon, who, let us remember, went to disturbing lengths to convince Ruki to be his Tamer.
Misblamed: It is not uncommon to hear Adventure fans to blame the change in universe and the darker tone contributed for Digimon's decline in the West. However, that's not the case, since the series had an unfortunate timing when it was released: 2001 was pretty much the peak of the Mons fad, and by the same time, Fox Kids (the program block that Digimon appeared on) was also being cancelled, leaving Digimon to appear on a different channel, at inconvenient times, which was also something that was already in motion before the Tamers dub even premiered.
Misaimed Fandom: Early on, Ruki was heralded by many Western female fans for being a "strong" character because she had a cold, no-nonsense attitude towards the other characters, which at the time was seen as a powerful breakaway from "Girly Girl" characters like Sora and Mimi. This also led to these very same fans losing interest in her once Ruki becomes a kinder, more emotional person, despite that the series has suggested for a very long time that this was her true self, and her rudeness was only meant to cover up her insecurities and loneliness, and she remains "strong" in the sense that she continues to take action and impact the plot.
Leomon's debut. It's supposed to look awe-inspiring, and maybe to an extent it does, but well... he's a lion for some reason rising-in-slow-motion from a rainbow even though he can't fly, and then proceeds to stand on it. How does he even do that?
Just like with Digimon Adventure 02, Fox Kids had a "Digibowl" special with Digimon Tamers to crossover with the Super Bowl promotions, where Terry Bradshaw would comment on action scenes in the show while communicating to Hikari and Lee's dubbed video clips.
Alice shows up for just one episode, but she proved to be so popular there are entire theories, fanart, and fanfics on her.
Among the Digimon that show up to fight the D-Reaper, one can spot Hououmon, Grankuwagamon and Plesiomon. Fans who knew that these were the original Ultimate forms of Piyomon, Tentomon and Gomamon were overjoyed, but the battle sadly happens off-screen, as the Digital World arc concludes just as they show up.
Similarly, two of the original Dark Masters and friggin' Diablomon cameo in the same scene, but have no lines and only serve as Fanservice.
Periphery Demographic: Although it's a kids show, Konaka wanted to create a show that adults can enjoy as well, and it shows by the large amount of adult fans, some who watched as a kid and appreciated the deconstruction elements more as they got older, and a few aren't even fans of the Digimon series as a whole! In fact, Konaka wrote the Digimon Tamers 1984 side story specifically for the adult fans.
Surprisingly Improved Sequel: After the divisive/disliked 02, Tamers is often viewed in the West as a much improved successor to the original series and is commonly praised for its much darker and more thematically complex writing. It helps that unlike the series that have come before or since, this is the darkest and edgiest that Digimon has ever really gotten. After all, this was penned by the same guy who wrote Serial Experiments Lain of all things, and the series edges so extremely close to the Cyberpunk genre it might as well be one.
They Wasted a Perfectly Good Character: Mostly averted for Beelzemon, who keeps up with the main cast in terms of importance and plot relevance... until his near-fatal injury at the hands of the D-Reaper. After that, he's completely side-lined, and Ryo takes his spot in the final battle, which for some is just rubbing salt in the wound.
When it first aired, many Western fans of the Adventure series were disappointed and confused by the lack of relation between the stories, and much of the theming and subtext was lost on younger viewers. Over a decade later, thanks to both access to the Japanese version in the west and a higher demand for more cerebral, deconstructive series, Tamers has gained a large amount of popularity, and is easily the second most popular Digimon series on both sides of the Pacific (not so much of the Atlantic, but it's still one of the ever-popular "Big Four" seasons in the European side).
How about Takato nearly causing The End of the World as We Know It? He's a Digimon fan. He's seen the series. He wears the goggles. He made his own Digimon that looks like a bigger, stronger, cooler version of Agumon. You'd Expect: Him to be careful not to go overboard forcing Guilmon to digivolve since he saw the episodes where Agumon was forced to digivolve by an angry, irrational person for all the wrong reasons, and should remember how that Went Horribly Right each time, resulting in massive danger and destruction for all involved. Instead: He screamed in rage and ORDERED WarGrowlmon to digivolve anyway, to get revenge on Beelzemon. Okay, yeah, Takato isn't the sharpest tool in the shed and was likely not thinking straight in the heat of the moment, but how did he expect that to turn out well?
In his defense, I assume he knows that there's a pretty high chance it'll go horribly awry, but is so absolutely CONSUMED by hatred that he simply doesn't care. Think of it as how some anime/comic characters know that a certain powerup will directly endanger them/their allies, but are so absolutely intent on wiping out the object of their ire that they decide to do it anyways.
Very much of the "was this content really created with children in mind?" variety. Head writer Chiaki Konaka, frustrated by the lack of gravity death is typically treated with by children's media, made it a point in Digimon Tamers for death to be permanent and traumatic. Which some people found rather troubling.
And, hell, one of the whole reasons for the Broken Base was due to feelings that the Moral Guardians might be in the right—showing the show to the later-elementary-age kids who are the (nominal) primary target of the show is a crapshoot as to whether they'll "get" it. Showing it to the kindergartenders on the young end of the target demo usually ends in tears and nightmares and is not recommended. (Of course, on the other end of the spectrum, these same elements made it and continue to make it vastly more popular with nearly every over-school-age periphery demographic.)
The very first episode. A Malidramon lunges at the jugular of a DarkTyrannomon, which explodes as it evolves into MetalTyrannomon, which then squashes the Malidramon with its palm. Pretty concisely sets up the stakes for the series' action beats.