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, from comedic rock group Elio e le Storie Tese. Also notable since, even while the whole song is sung by Elio, each line is in-character dialogue for one of the characters above (and lip-sync'd by them in the opening).