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.
YMMV: Higanbana No Saku Yoru Ni
Adaptation Displacement: Many think that like other 7th Expansion works, the manga is adapted from the VN. It's the opposite. The VN is simply taken as reference more often since it's considered better than the manga overall.
Complete Monster: Yoshihito Kanamori, a Sadistic Teacher and a dark, twisted version of the typical Lolicon you would normally see in anime, and he isn't Played for Laughs. He started as the homeroom teacher of Marie Moriya, a young girl bullied by her classmates. He used to defend her from the bullies, until the stress of his job got to him and he started to take his stress out on Marie. His supplementary lessons include molesting her and putting it on camera. When Marie gathered up enough courage to stand up to him, he strangles her to death, singing her a song about graduation from life to death while doing so, then dumps her corpse in the old school's septic tank. When he encounters Marie's spirit in the restroom, he gives her a long "The Reason You Suck" Speech about her not going to the police to report on him while she was still alive and called her an imbecile who couldn't fend for herself. He then opens the door to one of the bathroom stalls, and upon finding that Marie has apparently physically manifested, he tries to strangle Marie a second time. When the deed was seemingly done, he proceeds to rape the corpse when he notices it was still there.
Ensemble Darkhorse: Midori seems to be the most popular character after Higanbana and Marie, having amassed quite a bit of fanart.
Les Yay: Between Marie and Higanbana. In most of her talks with Marie, there would be a heart at the end of the speech. From this, you almost get the impression that she is flirting with her.
There's also some slight Ho Yay between Hameln and Hikaru in "Hameln's Castanets", when the narrative mentions that when Hameln leans towards Hikaru they're "close enough to kiss".