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.
Break the Cutie: There's a good reason for Akemiya to fall in this category, considering that he gets abused and blackmailed by his sister, molested by random pervs, made to confess to random girls, and later on, made to confess his love to Sumika knowing perfectly well that she's going to reject him, since she had done so already. And let's not forget that his budding modeling career gets offed in a freak accident. Granted, it's a comedy, but still...
Crowning Moment of Awesome: Tomoe defeating the previously unbeatable-at-anything-sports-related Sumika in swimming, made even more awesome as she blithely swam away after Sumika exhausted herself in the competition, showing that it wasn't even a challenge.
Sumika's "World of Cardboard" Speech in 16 is arguably hers, as she definitively stands up to Ushio instead of crumbling due to her feelings.
Sumika does this on a regular basis, but 17 is definitely the crowner.
Chapter 19 has several the heartwarming moments for Tomoe and Miyako, showing how genuine, pure, and unshakable their love is.
Chapter 21 brings us Sumika's thoughts on her Missing Mom, of whom she has very fleeting memories. For all the angst and problems she has with being not cute, she doesn't regret being born a girl because her mother was happy to finally have a daughter. D'aaawwww...
Ensemble Darkhorse: Kiyori's anime-incarnation makes a big splash with her dry "wha-ha-ha" laugh.
Fan Dumb: Referenced in-story by Ushio as the reason why she wants the fact that her older brother is a yuri author to be kept secret from Azusa, who's a fan of his work but thinks he's a female author.
Ushio: You don't understand the way fans think, Sumi-chan! The pure passion of teenagers can turn into negative energy all too easily.
Hollywood Homely: Averted, actually. Sumika is frequently addressed as "not cute;" however, this is not referring to her actual appearance, but her personality. As an assertive, outspoken sports-player, Sumika does not have the appeal of a "cute" girl. Just by looks, though...
Moe Moe: Sumika wonders how she could invoke this trope to appeal to Ushio.
Lotte out-moes them all. "German beauties are not to be trifled with!" Indeed, Sumika...
Aoi is sometimes disliked by fans as well, for similar reasons.
Special Effect Failure: The picture Noe-san uses in the anime when she likes to joke about how long she takes care of Sumika. She needs to know about Photoshop.
Tear Jerker: Poor Azusa, as she first realizes how Sumika feels for Ushio, then has it rubbed in her face about being the third wheel.
And in chapter 20, when we learn more about why Ushio is so Oblivious to Love. Specifically, the last person she seriously confessed to was another friend in middle school, who rejected her summarily as "disgusting." Ushio is so haunted by the fear that Sumika would reject her just the same that she gives herself the Just Friends speech. Poor Ushio.
The anime adds to the above Azusa Tear Jerker by playing "Sugu Soko ni Mieru Mono" the Insert Song for the anime.
The Woobie: You wouldn't think an Action Girl like Sumika could garner such a status, but it's hard not to feel sorry for her when Ushio blithely crushes her in the middle of their moments. Azusa and Akemiya both have moments where you feel really bad for them too, but that may not be to the strict letter of the trope.
Later Ushio becomes immensely woobie-fied herself, when it is revealed through flashbacks just why she keeps Sumika at bay.
Azusa gets one as well: "Was I...in the way?" She bounces back pretty quickly though.