Every time Miharu clinging to Minami, this classical high paced music is actually a good one.'
Ass Pull: The Class F Inquisition being able to increase their Avatar scores when they find out the class rep for Class B has a girlfriend. This is never explained, but probably occurred due to the Rule of Funny.
Broken Base: Whether or not Minami was redeemed or not in the event of her Day in the Limelight in Season 2. Some swear she's now the best girl in the school, while others still hate her with a burning passion.
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.
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.
Die for Our Ship: Akihisa/Minami shippers call Himeji a one-dimensional Generic Girl, Akihisa/Himeji shippers call Minami an aggressive bitch, and Akihisa/Hideyoshi or Kubo fans call both girls terrible influences who should be nowhere within two hundred feet of Akihisa. And woe betide you if you actually support Yuuji/Shouko...
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.
Idiot Plot: Mizuki getting sent to Class F because she had a medical emergency during the exam. Rather than taking the test again, she automatically fails.
Informed Wrongness: 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.
Shouko. She's the source of the most notable Double Standard: Abuse, Female on Male moments, and her obsession with Yuuji is at the very least, misguided, and at the worst, ungodly creepy. It doesn't help that she's quite a Karma Houdini, and the only time it looks like she might get some Laser-Guided Karma, it ends up working to her advantage. Notable in that her backstory does not excuse her actions at all.
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...
Unintentionally Unsympathetic: The narrative frequently suggests viewers are supposed to feel some kind of sympathy for Shouko. However, due to her actions as mentioned above, many readers and viewers have lost the ability to empathize with her, and would prefer to see her get what's coming to her.
Minami. Despite Yoshii being treated as wrong for constantly pointing out her violent nature, her Hair-Trigger Temper only serves to prove him right.
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.