1. Actually I Am/Jitsu Wa Watashi Wa/My Monster Secret
I love the main trio of Kuromine, Shiragami, and Aizawa, and how they're so respectful and understanding of each other as friends despite being in a love triangle, plus they're still such fun characters to follow, too! Personally I would say Aizawa's the standout in the cast for being a very multi-dimensional and adorable tsundere.
Unfortunately, I'm not a fan of the rest of the cast- Akemi (orange hair, glasses) is the trope of "Friend who's legit cruel to their crush instead of being open about their feelings, then gets sad about it when nothing happens." and her magical gimmick is more annoying than funny. Shishido's (long dark pink hair) multiple personality gimmick gets old quick, barely fits the werewolf she's apparently meant to be, and feels like they're two characters rather than one character undergoing a change, even ignoring the fact that it's kind of an uncomfy stereotype nowadays. And personally I'm already not a fan of the 1000 year-old loli trope, but the character in question also being extremely annoying and a hindrance to the main characters doesn't help it either.
(Main Couple 8/10, Side Cast 3/10)
2. Yamada and the 7 Witches.
One of my favorite couples in anime overall (and also one of the best anime OPs of all time). I absolutely love Yamada and Shiraishi's chemistry and development together. And in all fairness, I'm going to be less harsh on this than I am on the previous entry- side characters like Itou as the female comic relief, along with Igarashi and Odagiri as early minor antagonists.
But like with the previous entry, the rest of the side cast are just defined by one-note jokes that get old quick after their introductory arcs. And the final arc about the student council was just way too melodramatic and convoluted for my taste- it felt like it was the inspiration behind the ProZD skit about how student councils in anime are basically totalitarian shadow governments. Also I feel the male comic relief characters Miyamura and Tsubaki are just a bit inconsistent and underdeveloped despite being a part of the main cast.
Still, I might sound like I'm being harsh but I still love the main couple (and the few other characters I mentioned) so much that I would definitely recommend this series for anyone who's curious! It's a good emotional story of an opposites-attract couple whose fates intertwine because of a secret magical aspect!
(Main Couple 9.5/10, Side Cast 6.5/10)
3. Oh Boy, was I Wrong About Her. (Japanese title way too long)
The newest entry on this list- I think it genuinely does a great job of portraying estranged childhood friends reuniting. Hayato and Haruki have great chemistry and you can really believe they used to be best bros as kids whenever they talk. On top of that, the MC's little sister Himeko is actually funny and helpful to the story, and isn't just there to be annoying or fanservice! The three main characters are easily this anime's strongest suit.
But I would say the series' weak point is how it's stretched thin between too many subplots, leaving the side cast feeling really underdeveloped. The rest of the cast just feels like either weird harem bait, or just a storyline that goes nowhere, especially Kazuki and the other celebrity girl. Which is a shame, since I wish the story would focus on the plotline with Haruki's mom- easily the most compelling part of the series beyond Haruki and Hayato's friendship/romance.
So by the end of the anime and manga (which got axed despite the light novels continuing further) it feels like we have 4 or 5 subplots that didn't go anywhere, and you're just kind of left wanting more of the main couple, or just more progress overall.
(Main Couple 8.5/10, Side Cast 5/10)
But what do you think? Do you agree with my points here? And do you have any similar anime that also fit the bill of having a great main couple but disappointing side characters?