* AdaptationDisplacement: The TV series is much more famous than the series of novels it was originally based on. It's also markedly different from the original series of novels. In the books, Murdoch is much more of a DeadpanSnarker and is outright contemptuous of Brackenreid, and solves his cases through legwork and talking to people rather than any form of science. Inspector Brackenreid is depicted as an incompetent drunk who's also bigoted against the Catholic Murdoch. George Crabtree is described as having a large build and is a married father of five.
* EnsembleDarkhorse: There are many fans who are quite fond of Henry Higgins, and would very much like to see his character become part of the main cast. He and Constable Jackson have both been making more appearances since the beginning of season 8, often together with Crabtree, so it seems the writers have listened to some extent.
* FoeYay: Some fangirls began to ship Murdoch and James Gillies together after [[spoiler: the latter kisses the former on the mouth for a full three seconds in "Midnight Train to Kingston."]]
* HolyShitQuotient: Viewers all across the board were completely stunned when [[spoiler:Gillies kisses Murdoch rather passionately in "Midnight Train to Kingston"]]; ''no one'' saw that coming!
* PoliticallyCorrectHistory: While the racial and sexual biases of the era are prominent in the background, and often inform the cases being investigated, the central characters seldom espouse them, and if so only during subplots that require introspection and are resolved by learning the corresponding 21st-century value:
** Murdoch, a Catholic, initially receives some stick from Brackenreed for being a "Papist", but this is dropped relatively early.
** Murdoch also must come to terms with Dr. Ogden's abortion, both as a moral dilemma and because she's his OneTrueLove.
** In one episode, Brackenreed worries that his son might be gay because he wants to play a female part in a play. This leads to the boy getting hurt badly in rugby trying to impress his dad. While the boy's ultimate reasoning for wanting the female role (she had more lines) is later revealed and accepted, it doesn't come before Dr. Ogden has to talk Brackenreed into accepting his son's possible sexuality. In an episode set nearly ''seventy years'' before the decriminalization of homosexuality in Canada.
** Justified in the cases of Dr. Ogden and Dr. Grace, as two rare female physicians and pathologists during that period. Indeed, Dr. Ogden's unabashed statements of progressive views led to marital strain during her first marriage to Dr. Garland. In later seasons, we see her start an underground women's health clinic teaching birth control (which she was briefly arrested for), and vehemently object to the MaritalRapeLicense of the period. Dr. Grace, meanwhile, [[BiTheWay engaged in a same-sex relationship]]. Both were involved in the nascent suffrage movement of the early 1900s.
* TheWoobie: Whenever Murdoch breaks down and is NotSoStoic, especially when Julia told him about [[spoiler:her abortion and that it left her barren]] and implied that she wanted to break up their relationship.
* WhatAnIdiot: It's understandable that James Pendrick doesn't think much of Thomas Edison, given that the latter has been hounding him on suspicion that he's violating Edison's film technology patents. However, when you're an aspiring film director, it's probably not a good idea to turn down a job offer from the man who owns just about every movie screen in the United States, much less call him a "scoundrel" to his face.