Uzumaki/YMMV

Nightmare Fuel: What with it being intentionally horrifying - and does it ever manage!
Moral Event Horizon: Prior to their transformation to a mass of hedgerows, the refugees kicked out Kirie's family out of their very own place to make space.
Paranoia Fuel: You may not want to eat cinnamon buns for a long time!
- Which highlights another bit of paranoia: After a few chapters of Uzumaki, you'll start noticing the spirals all around you. Which is exactly how most of the characters start their "spiral obsession," which inevitably leads to madness, deformity, or death.
- The spirals in the story focus inward, so a good antidote after reading this may be to turn to the outward spirals of Gurren Lagann.
Squick
They Wasted a Perfectly Good Plot: For some, the fact that the series spends most of its time in a chapter-by-chapter format with little or no continuity is a point of frustration.
Values Dissonance: In western culture, burying a body in the ground as opposed to cremation is very common. But in Uzumaki it plays with the Japanese thought of walking ontop of dead bodies directly beneath your feet in graveyards to be deeply unsettling.
What an Idiot!: Jack-in-the-Box. "That's it! I saw something like this on TV! My love for you will STOP THIS CAR!"