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.
Why is Kamaitachi so crazy? Kamaittachi according to folklore work in groups of 3. What are the chances Kamaitachi is the sole survivor? Especially since in some versions the Kamaitachi are brothers. Or maybe hes a some kind of amalgamation of the three, he does have an awful lot of blades after all...
Hell Is That Noise: Kamaitachi laughing maniacally when he first appears at the hospital is an easy contender for creepiest laugh ever.
Nausea Fuel: The sound of someone wiping his ass. Yuck.
Episodes 4 and 5. To the point of episode 6 and the high-flying super-powered combat feeling like Mood Whiplash.
Ugly Cute: Pretty much every single true youkai qualifies, but especially Amefurikozo, the childlike snail-spirit who serves as Nue's Morality Pet.