YMMV / The Rats in the Walls

• Memetic Mutation: More one for Lovecraft himself, but ties into this story: Mentioning Lovecraft's/the narrator's cat and then refusing to say its name, causing some poor sap to google it and get a horrified reaction.
• Never Live It Down: Good luck finding any discussion of the story online that doesn't mention the cat's name.
• Science Marches On: An eminent scientist who examines the skeletons of the De la Poer’s human cattle cites the Piltdown Man, which was revealed as a hoax decades after the initial publication.
• Values Dissonance:
  • When he learns of certain vague "imputations of monstrous habits" made against his ancestors, the narrator finds their poor reputation "unpleasantly reminiscent" of a more recent scandal concerning one of his cousins, who "went among the Negroes and became a voodoo priest." Many modern readers are likely to consider this racist, both for implicitly calling the voodoo religion monstrous and for suggesting that living among "Negroes" and taking after their habits would be considered shameful for an upper-class white American.
  • Lovecraft's/the narrator's cat's name would have been more acceptable in the early 20th century, but to modern audiences it is an atrociously racist slur.
• Woobie, Destroyer of Worlds: Poor, poor Mister Delapore. First his family loses their home in the Civil War, his son dies in the Great War, and when he finds out what his family had done for centuries, he goes completely insane.