Anime fans get super invested in the pairings they like, and sometimes even more so in pairings they do not like. For every beloved anime couple, there exist anime characters who ended up with the wrong person. Sometimes, a perfect anime finale gets ruined by bad anime couples who never should have gotten together. A few of these ill-suited anime pairings appear below, so be prepared for some SPOILERS if you read on.
Many different reasons can help to explain why a relationship might be totally unappealing. Sometimes, the reason is obvious, like with Rin Kaga and Daikichi Kawachi of Bunny Drop. Even though Daichi raises Rin since she was 6 and he was 30, the two start a romantic relationship when she's 16. In other cases, the reasoning is more subtle and more subjective. A lot of people think Ichigo would have been better off with Rukia in Bleach, and get very passionate about it - but others like his canon choice to marry Orihime.
All of these poor anime pairings are up to debate, but the fact people debate them at all is not a great sign for their longevity.
Who Ichigo should have ended up with remains one of the most controversial topics in Bleach fandom. Ultimately, he ends up settling down with Orihime instead of Rukia. Unfortunately for the animators, the Ichigo-Rukia fandom makes plenty of good points in that pair's favor.
While Ichigo and Orihime care for each other, their relationship has some issues. For most of the series, Ichigo never appears interested in Orihime outside of needing to rescue her. Orihime isn't exactly weak, but her personality is a bit more subservient and uncertain than Rukia's, which creates an uneven dynamic. Her view of Ichigo is romanticized and unrealistic.
Rukia and Ichigo, meanwhile, act like equals who trust each other. She completely changes his life by granting him powers in the first place, and the two form a tight bond built on mutual respect (and some well-meaning bickering) from there. Which dynamic you prefer is largely a matter of personal choice, but Ichigo's relationship with Rukia is undeniably more grounded and realistic.
There's nothing especially wrong with Kayo Hinazuki's ultimate relationship, which is with Hiromi Sugita, a childhood friend who has always been sweet to her. The problem isn't Hiromi or the dynamic between Kayo and Hiromi. The problem is that the entire series builds up to a relationship between Kayo and Satoru Fujinuma, the protagonist.
Satoru goes back in time to stop Kayo from being slain by an unknown maniac who turns out to be their teacher. Over the course of his repeated attempts to rescue her, the two develop a genuinely meaningful bond. His final try is successful, but it ends in Satoru being severely harmed and entering a coma. He spends the next 13 years on life support, and by the time he wakes up, Kayo is already married. He's happy to see her happy, but the missed opportunity for these two still stings.
The reason Misa Amane and Light Yagami get together stems from Misa's obsessive devotion to the one she believes enacted justice for her late parents. Still emotionally raw from the trauma of their deaths, Misa is ill-equipped make good decisions about, well, anything. Light, meanwhile, feels no interest towards her romantically, but he does like the idea of using her to further his career as the "god of the new world."
What's disappointing is that they never move past this. Light distances himself from Misa when he no longer needs her help, only to happily use her when it's to his benefit. Misa deserves better than being a psychopath's groupie, and Light should probably be with someone who he can have a real conversation with. That is, assuming you believe Light deserves to be with anyone
Many fans suggest that Light is best suited for L, the detective trying to catch him. Intellectual equals with similar priorities and personalities, Light and L complement each other by forcing the other to be their "very best." The whole cat-mouse aspect of their relationship sort of ruins that theory, but it could work, especially when you consider how much they clearly value each other.
Misa, on the other hand, deserves someone capable of actually showing love - and that's Touta Matsuda. He's a kind, well-meaning person who treats everyone around him with respect. If Misa doesn't want someone quite that wholesome, she could date Kiyomi Takada, Light's other girlfriend. Seeing the two of them unite against Light would be a dream come true.
Kyousuke Kousaka has multiple romantic options, but he chooses to pursue his sister, Kirino, instead. The two even have a wedding - not a real one, since siblings can't legally marry, but a ceremony designed to celebrate their romantic feelings nonetheless.
Not only is this inherently unappealing to the majority of viewers, but it's still not a great relationship even if you are an inbreeding fan. Kirino is consistently cold and cruel to Kyousuke, showing no appreciation whatsoever for all the times he goes out of his way to help her. What's more, Kyousuke actually has a healthy relationship with Kuroneko before he randomly develops feelings for his sister, so this poor girl gets shunted to the side.
With a title like My Little Sister Can't Be This Cute, it's not like this development comes out of nowhere, but in the story itself, it feels arbitrary and unfair.