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: Seitokai No Ichizon
Big Lipped Alligator Moment — Mafuyu is holding a potato for much of the beginning of episode 10, but after Ken asks, "Why do you have a potato?", it is never seen or asked about again.
Made more intense after you learn the reason in episode twelve.
Episode 9:
Chizuru: Is your scar... all right now?
Episode 11 in its entirety. The girls learning first hand what Ken does on a daily basis, appreciating what he does, standing up for him, going to his home to help him out when he is sick, and then a love confession.
Genius Bonus — One Imagine Spot shows a group of boys going ga-ga over Minatsu teaching math. The writing on the blackboard behind her is a proof of Euler's identity, "the most beautiful theorem in mathematics."