Ear Worm: The opening theme, but especially the ending—yes, all five versions of it.
Moe: after all, the mangaka mentioned this series is drawn in puni-moe.
Tear Jerker: The last story in the first volume of the manga. More specifically, Professor, who can somehow speak to chickens, finds an abandoned newborn chick and decides to take care of it. It dies soon after, and she reveals to Kisaragi that she knew it would die all along, but she wanted to keep it comfortable until the very end. The next day, the two of them go to the chicken coop and find a whole brood of chicks, which the mother hen had been caring for.
True Art Is Incomprehensible: Noda fully exploits this when a solid block of pencil scribblings on a sketchpad is able to be viewed as "art" by everyone except for Namiko.
Noda: Um... it's called "Scratch Painting". Can you tell what it is?
Kisaragi: Ah... "Moonless Night"!
Tomokane: "Inside the Prof's head"!
Namiko: Looks like you just goofed off.
Noda: Everyone's so quick to jump to conclusions.
Sort of subverted, as that blob was intended to be a reverse canvas.
Values Dissonance: Professor once defiedIntelligence Equals Isolation by refusing to take higher-level typography qualifications despite qualified for them, so that she's on the same level with her classmates. More individualistic countries call this practice "dumbing yourself down," and not recommended that you do this in real life.