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.
Fridge Horror: In the room where Osanai peels the skin off Paprika/Chiba, there are hundreds of dead butterflies under the glass. Paprika is wearing butterfly wings during this scene. You do the math.
Harsher in Hindsight: All the talk about Konakawa's incomplete film. Paprika was Satoshi Kon's last completed project; he died partway through making another film called, coincidentally enough, The Dream Machine.
Nightmare Fuel: The mad dream parade, the scene where Dr. Osanai peels off Paprika's skin, the laughing doll (Brrrrr...), and the buzzing sound that appears when the doll is first shown in what appears to be the real world, or when Paprika sees Tokita asleep.
The parade does this especially well, considering it's an Amazing Technicolor Population of Grotesque Cute with an upbeat, cheery-sounding Ear Worm theme. There's something to be said of how the film makes terrifying a somersaulting frog whipping out drumsticks.
Subbing vs. Dubbing: A rare case where both sides have merits. The first meltdown dialogue comes off like a poorly translated metaphor in the subbed version, while the dubbed version makes it clear that the speaker's lost his mind. Interestingly, the dubbing goes for the spirit of the script rather than the translation, leading to entirely different but still effective dialogue.
Ugly Cute: Tokita, who may be morbidly fat, but has an expressive, cute baby face.