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.
Nausea Fuel: The water in the apartment is known to be dirty by the residents - Yoshimi even finds a hair in her glass of water early on. The reason for this? There's a decomposing corpse in the water tank.
The Woobie: Yoshimi and Dahlia. Ikuko also becomes one.