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.
Ear Worm: The opening and ending themes. The first comes with one of the most zany opening scenes ever made, also completely unrelated to anything and everything in the anime. The second with an incredibly addicting dance sketch that's just impossible to stop looking at.
The ending song's dance and the first manga volume's cover. Both Sonya and Yasuna are edited into other characters who are friends, enemies, siblings, etc.
Ships That Pass in the Night: Fans commonly ship Agiri with the Unused Character, despite the fact that the two have never had any real interaction in the show. Hell, the jury's still out on whether or not UC even knows Agiri exists!