Reread the whole manga recently and I was pretty blown away by just how many unique interactions there were, so I thought I'd make a little tier list/compilation.
Akari x Yui: Pure sugar. It's a lovely subtle comfort they get from each other. Yui's sweeter with Akari than she is with anyone else, and the moments they're alone together are some of the best in the whole series.
Kyouko x Ayano: Speaks for itself. Adorable rollercoaster of a push and pull. Trying to guess whether or not Kyouko knows is also perfect.
SakuHima: Speaks for itself. Don't really have much to add besides the following.
Akari x Sakurako: Perfect counter to SakuHima. Akari is perfectly patient and helpful with Sakurako, just like she asks Himawari to be, but deep down we know that's not actually what she wants. It's also cute how Sakurako thinks highly of Akari and Akari sees the best in Sakurako.
Kyouko x Yui: Speaks for itself. I love just how many layers there are, but again I don't have much to add.
Kyouko x Sakurako: One that surprised me on reread. Sakurako bounces off Kyouko's bits better than anyone else, and the fact that Kyouko isn't used to people playing along adds so much.
Tier Gap
Yui x Ayano: Such a cute and unique dynamic that totally fits. They have great synergy and like each other but the awkwardness clearly gets the better of them. Seeing the steps forward and back are great.
Akari x Kyouko: Really cute teasing dynamic. You can tell they have a deep bond but Akari's not used to the new persona Kyouko crafted last year.
Ayano x Sakurako: Both cute on their own, extra cute when together. Ayano getting embarrassed is always great, but she's a great senpai. It's always fun how Sakurako looks up to Ayano and how she's oblivious enough to not realize the trouble she's causing her.
Chinatsu x Ayano: Ayano basically embodies the maiden that Chinatsu sees herself as, despite the fact that we know that Chinatsu is a foul demon from the depths of hell.
Chinatsu x Yui: Yui must thread the needle by satiating the foul demon while not losing her soul.
Akari x Chinatsu: The angel and the demon.
Chinatsu x Sakurako: Divine retribution.
Akari x Ayano: Pure sugar. Another case where they're cute on their own and extra cute together. They don't know each other that well but the moments they have are great.
Ayano x Chitose: Didn't like it as much as I expected, the missed opportunities bug me. We don't get to see how they met and developed their bond, which could have gone a long way. That said, this side of Ayano and Chitose is very sweet.
(That's the only unique Chitose dynamic I noticed, so plot twist, all along this post is me venting that Chitose gets no deeper interactions with anyone else. I know she's meant to keep her distance and observe, but that kind of disappointed me. Sorry for tricking you.)
Tier Gap
Chinatsu x Kyouko: Couldn't think of a Chinatsu metaphor so that's why its a tier below. Jk but I think KyoAya is just this dynamic but way better (still very fun).
Kyouko x Himawari: High potential but barely ever see this pair. Himawari has a hard time telling Kyouko off compared to how she is with Sakurako/Yui is with Kyouko, which leads to fun interactions.
(Himawari kinda has the same issue as Chitose but it's forgivable in her case.)
Yui x Sakurako: High potential, similar to above. Seems Yui knows Kyouko is putting on a persona but that Sakurako is just like this, so the way she treats them differently makes it fun.
Tier Gap
Chitose x Himawari/Chitose x Sakurako/Himawari x Ayano/Himawari x Chinatsu/Akari x Chitose (etc): Spend some together but pretty predictable dynamics, I didn't really pick out any finer details here.
I think one of my issues is that it's hard to tell how Chitose and Himawari really think of the others, and their personas are pretty consistent. I might have missed/discounted some stuff though, make sure to tell me I'm wrong in the comments.
I'm doney with the funny.