These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Broken Base: There are some fans who enjoy this anime and there are some who dislikes this anime.
While the English Dub versus Sub wars of the show are currently minor, there are those who hates the Dub for its heavy editing and those who enjoys the Dub for fun.
Complete Monster: Slur, The Dragon to Big Bad Duo, is both a Knight Templarand a Complete Monster. Slur is fanatically devoted to exterminating all evil from the universe...where by "evil", she means everyone who doesn't agree with her master's extremely draconian concept of morality. In other words, Slur wants to kill all humans just because she doesn't like us. And unlike Duo, Slur has no sense of fair play - she deliberately "sabotages" the Humanity on Trial plot of Stream by giving Asteroid Navis to evil people, so that Duo will be convinced that Earth doesn't deserve to live. Vicious, sadistic, and with no redeeming qualities at all, Slur might very well be the vilest Battle Network villainess ever.
Crowning Moment of Funny: Possibly when Yai prevents Maddy from winning a net battle by reflecting the sun off of her large, waxed forehead, blinding her.
Crowning Music of Awesome: Shademan's theme from Axess. So much so that the Dub version used the same one as the Original version oddly enough.
Could be said of the series in general, once it hit its stride during Axess. The score during the original seasons were acceptable, with only a few notable themes. Sadly, more than likely because everyone had given up on it by then, the scores from Axess onward were never released - which is a shame, because that leaves fans attempting to sample songs for themselves.
Ho Yay: Netto and Enzan engage in quite a fair bit of this.
Misaimed Marketing: Even back then a lot of people thought that the show would have been a lot better off on Toonami than Kids WB, granted back then Kids WB was pretty much alive and well but still...
Moral Event Horizon: While Duo judging planets on whether or not they should be destroyed already means he's likely crossed it well before the series began, It turns out that he crossed it when he destroyed his own planet, it wasn't for any good reason either, he just decided that he had the authority to judge whether entire species have the right to exist and felt that his creators didn't.
Clarification: Duo, the ominous power hovering over the planet for most of the season, has the power to unmake and remake the entire planet and every human being on it. No way is any battle going to bridge that gap. So the writers reached out deep into left field.
The Scrappy: Slur. Part of the hate for Stream is because of her invincibility, coupled with her prominence and how appallingly evil she is. Likely because of this the season ends with beingbrutally murdered by Bass.
Seasonal Rot: Every season can get accused of this. Axess gets accused of it for the shift in tone, Stream gets it for exaggerating it further, Beast Plus for basically becoming a stream of Filler. Every season has it's fans, though.
Villain Decay: The WWW starts out as a fearsome organization bent on domination of both the real world and cyberspace. By the middle of season 1, they're running a curry shop together, where they have no qualms about cheerfully serving the heroes. They claim to be just as devoted to evil, though.
What an Idiot: In episodes 18-19, Maylu putting on the chip without knowing of the effects on Roll. Additionally, Roll herself didn't try to get suspicious on the chip she has at the time.
Also, MegaMan being fooled into thinking that Roll is back to herself despite her form is not yet normal counts as this.
Jerkass Woobie: In Axess, Chaud himself suffered majorly when he was forced to use a Dark Chip on Protoman.EXE to save not only Lan and Anetta but Megaman as well. While Chaud was rather cold to Lan during their confrontation episodes later, you can't help but to feel bad for the guy.