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.
Idiot Plot: A mild example — perhaps more of a None-Too-Clever Plot. But it really should be obvious to anyone paying attention that something odd is going on between Aoi and Kaoru; even the way they address each other — Aoi calling the ostensibly lower-caste Kaoru "Kaoru-sama" while Kaoru calls the ostensibly higher-caste Aoi "Aoi-chan" — should make people suspicious. Even more egregiously, while Aoi and Kaoru may have reason to keep their engagement low profile to avoid antagonizing Aoi's family, there's no good reason for Kaoru to pretend he's romantically "available," except that it keeps the "hilarity" going.
Averted in the manga, where, in spite of being sidelined or downplayed for comedic purposes most of the time, it is made fairly clear that Aoi's family is putting extreme pressure on Aoi and Kaoru to avoid giving any sign of being in a relationship. They even go so far as to actively attempt to break them up by trying to get Aoi to marry another man. This persists all the way up to the final volume where Aoi is practically kidnapped in an attempt to get her to marry the other Kaoru who is supposed to be the new heir to Hanabishi clan. It's made clear that Aoi's father has been opposed to her relationship with Kaoru up to the very end. This troper is a little surprised that her father didn't put out a hit on the guy (you know, aside from the fact that that would have comprised the author taking the genre and structure of his story and breaking them over his knee).
Subverted with Tina, who later admits that she did notice the attraction Kaoru and Aoi had for each other, but had doubts and (unaware of both their upper-class statuses and the enforced Cannot Spit It Out) couldn't begin to guess why they were hiding it.
Les Yay: Tina likes groping other women's (and girls') breasts. But she's really in love with Kaoru. Also, there's her threat to go kiss Aoi and Miyabi if Kaoru won't kiss her.
Miyabi's life revolves around Aoi, and she admits feeling jealousy toward Kaoru, as well as a belief that he is unworthy of all the effort Aoi has been putting in to prepare for being his wife.
Played with when Tina discovers Aoi's habit of hugging people or objects in her sleep. She tells Aoi the next morning, "I thought I was going to have to switch teams just to survive," and there's an Imagine Spot of a wide-awake, seductively smiling Aoi fondling her. Meanwhile, the real Aoi is going into spasms of embarrassment, complete with Luminescent Blush and Big "NO!".
Marty Stu: Kaoru fits the bill completely here with a tragic backstory and the ability to basically attract any girl he meets without any real effort behind it.