The Scene at the very end of Chika's character song at the end of Episode 3, where Chika releases a small bug back into the Wild, is based on a Manga Chapter that wasn't adapted in the Anime, in which Shirogane attempts to hide his fear of the Bug from Kaguya; in the end, Chika gets praise for "her Bravery" from Shirogane when she releases the Bug for him.
Ian Sinclair's version of the Narrator in the English Dub is significantly different than the Original Japanese's version, voiced by Yutaka Aoyama. Aoyama plays the Narrator Straight, as if studying the Characters in the same vein as a Documentary, while Sinclair is more playful, cracking jokes & laughing (most likely Improvisation on Sinclair's part).
A large portion of the Opening sequence & the Marketing focuses on Old Maid playing Card; however, Chapter 2, the Chapter in which they play Old Maid, never made it into the Anime.
Shortly after the Third Season Aired, the Series briefly took the Top Spot on MyAnimeList's Popularity Poll with a Record Breaking 9.15 approval Rating, taking the Spot usually held by Fullmetal Alchemist: Brotherhood.
After being cast in the English Dub, Cover Artist Amalee (who voices Hayasaka) did covers of both of the Show's Opening Songs.