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.
Crowning Music of Awesome: The ending theme, "Musuhi no Toki," sung by Nagi's voice actress, Haruka Tomatsu. Creating Soundtrack Dissonance with the show's overall tone, it's a sweet, soft-spoken lullaby-like tune composed in very archaic Japanese that brings the show's religious elements to the fore.
Memetic Mutation: Nagi's karaoke sequence has been edited with several Touhou characters and characters from other anime.
Tastes Like Diabetes: Takako's cutesy-pie song and dance routine (in episode 10 of the anime) is so saccharine sweet (and so at odds with her usual demeanour) that the rest of the Art Club are appalled.