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.
Ironman is the wild card in the show, as he can allow battles in any subject.
He's surprisingly empathetic, intuitively understanding why Mizuki needs to alter her 2nd placement test. He also correctly guesses that there's an important reason for Yuuji and Yoshii's hijinks. See CMoA below.
Every time Miharu clinging to Minami, this classical high paced music is actually a good one.
Designated Hero: Most of Class F. Minami is a violent Tsundere, Yuji is a slacker, Kouta is a future sex offender, and Himeji devolves into Minami 2.0.
Designated Villain: Yoshii in episode 10 of the second season. While he may have somewhat deserved the harsh treatment he got, he isn't the only one at fault. He may treat Minami like one of the guys, but that's partly because she's always beating him up, at times with only the slightest provocation. Not to mention, Miharu is one of the last people to tell Yoshii that he doesn't treat Minami well. Especially since she gave the What the Hell, Hero? speech right in front of Minami, and reduced her to tears.
Dude, Not Funny!: Some of the ways the girls abuse the guys, especially Shouko, would either cause them to get hit with restraining orders and/or jail if it happened in real life.
Akihisa's constant poverty is Played for Laughs, In real life, if a case like this with a minor living on their own, unable to really take care of themselves was sighted, they'd be taken away by social services.
Mizuki, as far as Class F students go, having the brains of a Class A student.
Fighting Kouta in a Health and PE match is tantamount to suicide. His scores are so high in these subjects he can easily defeat Shouko, a Class A student and the best one in their year. Kouta actually kicks this Up to Eleven with the reveal that he has a score higher than the teacher of said subject. Too bad he can't pull that in all subjects.
Kicked into overdrive by Episode 3 with Akihisa and Toshimitsu. Kouta took a picture associated with the love letter. Episode 5 also has Toshimitsu unable to open Akihisa's locker out of fear someone would think he was putting a love letter in it.
In Episode 6 Akihisa imagined Hideyoshi in a swimsuit, once again surrounded by Bishie Sparkle. Followed by joining Kouta in the Corner of Woe when Hideyoshi decides to wear trunks, only to be subverted when Hideyoshi comes out wearing very girly trunks and a swimsuit. Cue both guys having nosebleeds until they've ran dry. They start nosebleeding again when Akihisa accidentally pulls Hideyoshi's top off.
Season 2 Episode 9: Hideyoshi shows Minami how acting's done by way of a very convincing faux-confession.
Convincing? Akihisa himself said he didn't want his dream to be over yet.
In Episode 8 a malfunction of the Summoning System leads to a quite... interesting scene between Yuuji and Kouta's avatars. It doesn't help that both have been turned into Bishonens.
And in Episode 9, we have the Yuuji-Akihisa combo from Episode 1... and it's back with twice the implications and triple the dose!
The Christmas Episode DVD extra has the characters being asked by the Narrator what Christmas means to them, before the cult members of class-F interrupt them to correct them. It starts with Himeji, then Minami, then Hideyoshi, then Akihisa/Yuuji/Kouta. All of them are played out in the exact same sequence, ending with a tall male character walking up to them, with the camera panning close to their feet while they lean up to him for a kiss. Yes, even for the guys.
The cult members all beg Hideyoshi to go out with them at the end of his segment.
As Of Volume 10 Akihisa has official kissed another guy on the lips, although to be fair he didn't mean to.
MiharuShimizu as well. Season 2 made things worse in her case as well. And she doesn't really get better, unlike Minami. Her only saving grace is perhaps the fact that she's voiced by Ayana Taketatsu, but even then...
Unfortunate Implications: In Class F there are only 2 girls, one of which is only there because of illness, while the other is only there because of her difficulty reading the kanji. Can only guys be truly stupid?
Abusing Yoshii is funny and sad at the same. And then there was that one time he took that history exam and got a zero because he wrote Alexander the Great where his name was supposed to be.
Shouko gets a rare one in episode 7 of Season 1, when she runs off stage in a wedding dress after getting mocked by another couple that she's got a stupid dream of wanting to be Yuji's bride. Yuji decides to have a little "talk" with said couple later on, and presumably beats up the guy, as he looks like he's been in a fight after he catches up with her later on.