Agatha Christie got tired of writing Poirot novels, describing him in 1930 as "insufferable" and in 1960 as a "detestable, bombastic, tiresome, ego-centric little creep". However, since she saw how popular the character was, she felt the obligation to continue giving his fans more Poirot stories, which she did until 1975, one year before her death. As the quote at the top of the main article suggests, Agatha Christie much preferred her other character, Miss Marple.
In-universe in Mrs. McGinty's Dead, Adriane Oliver delivers nearly the same quote when talking about her own character, a Finnish detective with a bizarre quirk (he grates his vegetables before eating them).
Disowned Adaptation: Christie was reportedly not happy with the results of The Alphabet Murders (1965) due to its more slapstick tone (mimicking that of the Marple films of the same era which she was similarly critical of).
What Could Have Been: According to 'Agatha Christie's Secret Notebooks', the original 'Capture of Cerberus' was very different and was rejected by the publisher.
