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.
YMMV: The Graveyard Book
Big Lipped Alligator Moment: The Danse Macabre is an in-universe example of a Big Lipped Alligator Moment. One day every eighty years or so (which is probably not coincidentally about once in a human lifetime), white flowers bloom in the graveyard and The Grim Reaper leads a dance between the living and the dead. Even people who are not aware that ghosts exist proceed about like this is normal, but the living cannot remember it after it happens and the dead are forbidden from talking about it with the living. Those who are not living or dead, such as Silas, cannot participate in the Danse Macabre and Bod questions him about the sheer BLAM-ness of it after he finds out that none of the ghosts will discuss the events of the previous night.
To be more specific, the part where Jack Frost is "protected" by the Sleer. Although there are a few more segments that could fit this trope, like the fate of Nick and Maureen. But none are as bad as that first one.