* AdaptationDisplacement: While the books are very popular, the 1998 series tends to be a little better known. A lot of details from the show - like Miss Bat and Miss Drill's AdaptationPersonalityChange, Maud's surname being Moonshine, Ethel being a RichBitch - are mistaken as book canon. Jill Murphy even ran with it, notably expanding Drusilla's role in books written after the TV series. The TV movie is mostly forgotten, except for a few nostalgic fans.
* AlternateCharacterInterpretation:
** Mildred's status as the Worst Witch in the school is up for debate. On the one hand, she is quite bad at a few things. But on the other, she seems to be mainly bad in the school environment. The main problems that her teachers have is that she's accident prone, occasionally lazy and quick to break the rules. Once she's got the proper theory down, she doesn't seem to have any problem casting magic in the field. She also notably gets over her fear of heights through consistent broomstick flying - suggesting she might be BrilliantButLazy and fully capable of getting high marks if she applies herself. This is also shown in the 2017 series within the first episode, wherein Mildred is quite capable of creating a Levitation Potion correctly the first time she does so, simply because she is applying her fully to working on said potion.
** Miss Hardbroom's attitude towards Mildred is also up for debate. There's reason to believe she just has a vendetta against the girl - as there are a lot of incidents where she shows blatant favouritism to Ethel and is quick to punish Mildred without giving the latter the benefit of the doubt. One has to wonder how much of Mildred's ineptitude stems from Hardbroom's treatment of her. On the other hand, Miss Hardbroom is always happy whenever Mildred does well in class - and she'll always sincerely thank Mildred whenever she saves the day. So it might be that Hardbroom thinks Millie is BrilliantButLazy too - and her dislike could be that she thinks Mildred is wasting her potential. It can be argued that the 1998 series' Miss Hardbroom is portrayed with this attitude in mind. Also a case of FridgeBrilliance: of course Mildred would see her stern teacher as unnecessarily harsh, she's the one who's often in trouble. As the audience we are allowed to see that there is more to HB than her strict attitude, and high standards.
** With regards to Ethel and Drusilla, how much does Ethel care for her? There are times when Ethel seems to view her as a servant rather than a friend. Other episodes show that she does seem to care for her to some extent. Given that Ethel has no other friends, and appears to be a bit of a DaddysGirl, it's possible she wants a friend but doesn't know how to behave towards one. The books seem to regard them as allies only, as the other girls find Ethel's attitude too much. The 2017 also suggests in it's first episode that Ethel may have a slight inferiority complex, due to living in the shadow of her equally brilliant older sister. However, it can be said that Ethel's sister seems a little wary of Ethel, so whether or not this is the case remans to be see.
* BaseBreakingCharacter: Hobbes from ''Weirdsister College''. Some give him the DracoInLeatherPants treatment due to his FreudianExcuse. Others find that it doesn't justify his awful behaviour and think he's unnecessarily dickish. And then there's the third group who are arguably a mix of both sides of the argument, thinking that while his past makes his motivations understandable, he does need to check his behaviour.
** Any replacement teacher (or actor) is more likely to become a subject of this trope. Especially when it comes to fan favourite, Miss Hardbroom.
* CounterpartComparison: Given the ''Literature/HarryPotter'' similarities, Ethel gets compared to both Draco Malfoy (for being TheRival who's also a RichBitch) and Hermione (for being an AcademicAlphaBitch). It's theorised by some fans that Ethel is what Hermione would be if she had never made friends with Harry and Ron.
** Even more blatantly, Miss Hardbroom gets compared to both Minerva [=McGonagall=] (for being the stern, no-nonsense Deputy Headmistress) and Severus Snape (for teaching Potions and for heavily disliking - or at least having a complicated attitude towards - the main character). However, among certain circles of the fandom, comparing Hardbroom to Snape is a bit of a {{BerserkButton}} and best avoided if at all possible.
* EnsembleDarkhorse: Miss Bat is the most popular of the teachers with fans. It's quite surprising given that she made one appearance in the books. Likewise Drusilla was well received - enough for Jill Murphy to feature her more in books that were written after the TV series.
** Arguably it can be said that 'all' the teachers would fit under this tropes, as this series is written largely from Mildred's point of view, and she does not often get on with her teachers even with the best of intentions.
** For non-book characters, Charlie Blossom as well - presumably for the {{Shipping}} potential. One episode character Deirdre Swoop also got upgraded to regular in both spin-offs.
** Clarice is also rather popular for someone who only made a brief appearance in the books and was in a supporting role for most of the TV series.
* FanPreferredCouple: While pairings regarding Mildred herself will be varied within the fandom, older fans - particularly those who grew up with the 1998 iTV series - seem to have a preference for Miss Hardbroom/Miss Drill. It remains to be seen if this will carry over with the 2017 CBBC series.
** Also popular, again among that particular circle of fans, seems to be Fenny and Gris, the two friends who are never seen without the other. It's very easy to read a relationship into that. Though, considering that Cackle's is an all-girl's school, it would be easy to read any friendship as romantic.
* FridgeBrilliance: The most obvious example would be seen in the portrayal of Miss Hardbroom in the adaptations. While Mildred sees her as a teacher who hates her, the audience are shown that this is not the case, it's simply that Miss Hardbroom thinks that the girl keeps jumping into trouble without thinking about the consequence (this is outright confirmed in the first episode of ''Weirdsister College''.) But of course that wouldn't be obvious in the books - they're all from Mildred's point of view.
** Ethel gives herself a "witch-over" in season 2 because she's embarrassed by her sister (explaining why she is played by Katy Allen). However in ''Weirdsister College'' she is played by Felicity Jones again. Now she's at college where her sister isn't there, she doesn't have to worry about being embarrassed by her so she removed the "witch-over". Likewise Deirdre Swoop doesn't recognise Ethel in the first episode because she had only seen her witch-over self.
** It's stated in the first episode that the right words in spells aren't as important as the right feelings. Episode three deals with Ethel being turned from a pig into a duck by Charlie getting the spell words wrong. The brilliance is that Charlie has not been educated in magic at all so he can't rely on "the right feeling" - so all he can go on are the words to the spell. Alternately he might have been concentrating on "turn Ethel back from a pig" but not concentrating enough on what to turn her ''into''.
** Closely related is Enid's spell for food in "Let Them Eat Cake". Like Charlie, the spell fails because of the last word. Both she and Charlie put emphasis on the last word in the incantation - resulting in the wrong effects. Charlie says Reduccio as "re-DUCK-io" so Ethel is turned into a duck. And Enid says "make it hasty" and gets them showered with hay. Also for Enid's spell - hay can be a snack for animals. Enid just wasn't being specific enough that she wanted food for herself.
** Why are spells in Latin when any incantation will do (coupled with the right feeling)? Because Cackles prides itself on tradition and Latin was what the upper classes wrote books in back in the days the spells were invented.
** Why doesn't 'Miss Cackle' notice the other three teachers spying on her class in "A Bolt From The Blue"? [[spoiler: Because Agatha can't see properly through Amelia's glasses]].
** The 2017 gives a new case: it's stated in the books that it is tradition for girls to fly into Cackle's. However, as there is the strong implication that magic is not widely known, it can often be asked why no one has spotted a girl on a broomstick before, especially in the village near Cackles. According to the 2017 series, it is because the broomsticks are made to have enchantments that prevent non-magical people from seeing them in flight.
* HilariousInHindsight: Fairuza Balk playing the titular Worst Witch in the TV movie. She would go onto become a practising Wiccan in real life later - and would play an Ethel type in ''Film/TheCraft''.
** Felicity Jones originally played Ethel Hallow in the 1998 iTV series. Ethel is very much a stickler for the rules, and loathe to disobey authority. Fast-forward 18 years, and Ms Jones is appearing in ''Film/RogueOne'', fighting against the Empire - very much the authority in the galaxy.
** The 2017 CBBC incarnation of the show casts Bella Ramsey as Mildred Hubble. Surely this means, if Cackle's faces any trouble, Mildred can simply call on her banners...
* IronWoobie: Miss Drill if you think about it. She's one of the few non-witch members of staff (in the TV show anyway) and is constantly at odds with Miss Hardbroom. Although she experiences plenty of FantasticRacism, she just keeps on with her job and trying to do her best.
** Mildred herself could also be considered as an example of this trope. Even though it seems as if the world is against her trying to become a witch, she constantly continues to push herself forward. In the television adaptations, she is also a victim of FantasticRacism, being a magical person from a non-magical family. It's implied that this is rare, and Mildred is stated to be the first student of such background in Cackle's.
* LesYay:
** In ''The New Worst Witch'', Dyllis Mustardseed seems to be crushing pretty hard on Belladonna Bindweed. Too bad Belladonna hates her.
** The bickering between Miss Drill and Miss Bat in Season 2 could slip into this at times.
** This is also seen to be the attitude between Miss Hardbroom and Miss Drill.
* {{Narm}}:
** Merlin trying to reseal the Dragon Lord back into the cave. He says "Back from whence you came" as if he couldn't care less.
** Miss Drill's evil persona as Hilary Hemlock. EvilIsHammy to the last degree.
** While Sybil is an effective Woobie, any time she actually has to cry on screen, it's painfully forced.
* OlderThanTheyThink: An isolated medieval castle containing a magic school, with a forest nearby? A protagonist who has no prior knowledge of the magical world? A rival who comes from a leading magical family? A hook-nosed Potions teacher who favours the rival and despises the protagonist? A kindly, grey-haired Head who befriends and helps the protagonist? Classes in Charms and broomstick riding? While both ''The Worst Witch'' and ''Harry Potter'' clearly have very similar elements, Jill Murphy's series predates the latter by 23 years, with the first book being published in 1974.
* PainfulRhyme: Tim Curry's big song features every conceivable word that rhymes with "Halloween," and many that aren't.
* ReplacementScrappy:
** Katy Allen for Felicity Jones as Ethel. Likewise Ted Blossom being an {{Expy}} of his brother Frank. Averted with Miss Crotchet, despite replacing the fan favourite Miss Bat.
** In ''Weirdsister College'' Cas Crowfeather gets a bit of hate for replacing Maud as Mildred's best friend.
** Caroline O'Neill replacing Kate Duchene as Miss Hardbroom in ''The New Worst Witch''.
* TheScrappy: Jadu has very few fans in comparison to the rest of the main cast - mainly due to her role as TheGenericGuy and her actress's wooden delivery, as well as lack of focus until the very end of the series
* SpecialEffectsFailure:
** The music video made by Tim Curry aka the Grand Wizard. [[http://www.youtube.com/watch?v=PUhuPn8_d0Q Really, see for yourself.]]
** The flying effects on the 1998 TV show zig zag between this, while being respectable enough for the era, especially on the small budget allocated to the children's TV show.
* TheyWastedAPerfectlyGoodCharacter: Ruby zigzags through this. While she does get a couple of more focus episodes as the series goes, she's still very much an obvious TokenMinority. Jadu meanwhile gets only one day in the limelight - which is the second last episode. In this case it's slightly justified by her actress just not being very good.
* UncertainAudience: The spin-off ''Weirdsister College''. It's DarkerAndEdgier, Georgina Sherrington claiming it was aimed at a slightly older crowd. But the acting and effects are still quite similar to the parent show, alienating a lot of potential older viewers. Meanwhile the show was a bit too dark and serious for the crowd who had grown up with ''The Worst Witch''.
** Though that's not to say that it does not have its' own fans, and the idea of magical education beyond the high school level being shown is one that was happily received.
* TheWoobie:
** Sybill Hallow. It's clear she has high standards to live up to, and she finds Cackle's terrifying at first. The fact that her sister is so embarrassed by her that she changes her appearance in the hopes no one will know they were related just adds to it. This line sums up Sybil perfectly.
--> "All I want is a sister. A real sister. Not a bossy-boots like Ethel."
** Mildred herself also has some aspects of this, since some of the staff seem to want her to fail. In the Season 1 finale of the 1998 series when Miss Cackle appears to have gotten sick of her, Millie looks like she needs a hug. Ditto for the HalloweenEpisode where the whole school turns on her for her pratfall at the display. This also continues in the 2017 series, where Mildred seems heartbroken when she is faced with the knowledge - in the first episode - that while she can see this magical world, she cannot be part of it due to failing the entry exams for Cackle's.
** Dyllis Mustardseed in ''The New Worst Witch''. It's very hard not to feel sympathy for Dyllis. She's a nervous flyer in a school that insists on broomstick flying as a mandatory exercise, seems to fade into the background a lot, and doesn't seem to be especially brilliant in any of her subjects. The poor girl willingly spends time with Belladonna even though she knows the girl treats her as a servant simply because she has no other friends. She ends up taking a powerful potions book from the library as it contains the recepie for a popularity potion. When Hettie is in danger of being expelled, she comes forward with the truth and, thankfully, from that moment on she seems to be included as a sometimes fourth to that group of friends. When the writers remember.