- Fan-Preferred Couple: "Agatha Christie's Secret Notebooks" reveals that Lucy Eyelesbarrow (Miss Marple's main proxy in 4.50 from Paddington) would eventually marry Cedric Crackenthorpe, whom many fans detest. Most would rather see her end up with Inspector Dermot Craddock (whom she interacts with only once or twice), or remain single and independent like Miss Marple herself.
- Foe Yay: Inspector Neele and Mary Dove in "A Pocketful of Rye".
- Moral Event Horizon:
- The murder of the Girl Guide to establish an alibi for the first murder in The Body in the Library.
- The use of Gladys as a cat's paw and then her murder when she had outlived her usefulness in A Pocket Full of Rye.
The ITV series
- Broken Base: The series sparked a lot of controversies due to the liberal changes it makes to the original source material. These changes includes: adapting novels that is not originally a Marple story, switching around the characters' personalities, changing the murder motives and even the identity of the murder,
- Hollywood Homely: "A Pocketful of Rye" had the supposedly-plain Elaine Fortescue played by the decidedly beautiful Hattie Morahan, looking her best in fashionable clothes and an elaborate hairdo. Despite this, the other characters were at pains to point out how unattractive she was.