- At the end of the story, we find out that Lettie is still alive, but still, as of yet, unable to talk or move about. It's implied her healing may take much longer than the narrator has to live, so while she will survive the ordeal, he'll never get a chance to actually talk to her again.
- The narrator mentioning that it took him to the age of 20 to actually become friends with his father, who he felt might have been disappointed by his bookish son.
- There's also the fact that, after remembering what happened regarding Lettie and the Hempstocks, the narrator forgets everything all over again. Keep in mind he hasn't thought about Lettie in decades at the start of the book.
- The Reality Subtext behind the book, dissected to death in this article. Neil Gaiman started writing the story as a memoir for Amanda Palmer, after all, so the truth inspired it.
Tearjerker / The Ocean at the End of the Lane