The books
- The aftermath of the Halloween fiasco. Ethel bewitched her broom to buck Mildred off, making it look like her clumsiness ruined the celebration. It's especially sad because the display had been going so well before, with one witch telling HB "your girls get better every year". Everyone blames Mildred, who we should remind ourselves, is only eleven. It's said that "even Maud was being very cool towards her friend". No wonder she decides to run away.
- Mildred's self-esteem is so low that she imagines they'll throw a holiday at the school celebrating that she's finally gone.
- Maud's Face–Heel Turn in The Worst Witch Strikes Again. It stings because Mildred has to go around with Enid on Miss Cackle and Miss Hardbroom's orders, and Maud decides to hang around with Ethel instead. Thankfully she redeems herself big time in the climax.
- In The Worst Witch All at Sea, Miss Hardbroom gets knocked unconscious and stays that way all night. She's woken up the next morning, but will have to be in bed for the rest of the holiday, which is unpleasant, especially for someone like HB. Worse still, Mildred doesn't mind, in fact she's glad.
- Mildred having her beloved cat Tabby taken off her because the other teachers disapprove of him. Before she has to give him away, Mildred tearfully suggests she get up earlier every morning to really train him to be more comfortable on a broomstick and even making a black coat to hide his stripy fur.
The 1998 series
- The way Mildred is treated like crap in "The Battle of the Broomsticks", the first episode of the 1998 series.
- Due to being from a non-witch family, she gets lost making her way to Cackle's, and Ethel refuses to let her fly on her broom to save her image. And just to be spiteful for Mildred throwing a branch at her, she pretends she doesn't know about a Mildred Hubble who's lost in the forest when the teachers call the register.
- Locked out of the school by the time she finally gets there, Mildred tries flying over the gates. She's afraid of heights, and is screaming in terror as she has no idea how to get down. Were this not a children's series, she could likely have seriously hurt herself. Just to Kick the Dog, Miss Hardbroom snaps at the other girls for rushing to help her.
- HB gets in another nasty dig at Mildred in their first class, making her write lines for looking tired.
- Drucilla establishing herself as Ethel's Beta Bitch by laughing cruelly at Mildred taping her broken broomstick together.
- Mildred overall wants to be a witch and to do well in her classes, but her fear of heights is so overpowering she's convinced she'll fail before she even starts.
- When Ethel sabotages Ruby's plan to help Mildred pass the test, she crashes again and all the girls laugh at her.
- The end of the first Halloween episode - as Ethel casts a spell on her broomstick to humiliate Mildred. It's slightly worse than in the book - where Mildred is bucked off and causes the other girls to fall off as well. Here it's only Mildred that gets humiliated and she crashes into the Grand Wizard. The book also only says that "even Maud was being very cool towards her friend" - but the TV series has Maud outright ignore Mildred after it happens.
- 'Miss Cackle' going ballistic and locking Mildred in her room in the season 1 finale. Mildred gets dragged from the classroom by her ear, abuse yelled at her in the office and is confined to her room just after she's told she's expelled. Even Miss Hardbroom is shocked by this behaviour. The kicker is that this is triggered by Ethel pranking Mildred in class. It's made a little better since it's only Agatha Cackle impersonating her sister.
- The end of "The Unfairground" when Jadu and Mildred are expelled from Cackle's. What makes this even sadder is that Miss Cackle still gives them a Pet the Dog moment - rather than have their permanent records ruined with an expulsion, she'll write a letter to their parents asking them to just withdraw them from the school.
- The episode "Good Friends" of Weirdsister College. Enid shows up at Weirdsister and, while she and Millie have fun at first, it's soon apparent that they've gone in different directions. And in the end the girls both realize that they can never be friends in the way they were back at Cackle's.
- On a related note, the very real possibility that Mildred might have had to give up Tabby to prove she was ready to continue with her studies. She's almost tearful when she puts Tabby on the wheel, and poor Tabby looks back at her in confusion. Had Enid not appeared and agreed to offer their friendship in Tabby's place, this would have been the last time Mildred would have seen her beloved cat.
The 2017 Series
- A minor one, but Beatrice Bunch seems so sad when she reveals that she's allergic to cats. Thankfully, Miss Cackle makes it better.
- In the 2017 series, Mildred suffers from a severe lack of self-esteem, constantly being belittled and suffering a series of accidents which make her look even worse, while doing her best to win any respect from her peers at all. When she finds out in the series 2 finale that she is descended from a witching family, she's overjoyed.
- The whole premise of Maud's Big Mistake is a pretty emotional It's a Wonderful Plot episode, in which Maud uses forgetting powder to erase everyone's memories of her mistakes, but also erases her friendship with Mildred from everyone's memories, including Mildred herself, since everyone considers that to be a mistake. Imagine how it would feel if you not only caused your best friend in the whole world to forget you and all the good times you had together, but also found out you were the only reason they hadn't been expelled from school since they had you to help them stay in line....and now that the principal has forgotten your friendship, they have no faith that your friend can succeed and is going to be expelled..and it's all your fault. Perhaps this is why the staff discourages using magic for selfish purposes.
- Maude turning on Mildred at the end of the penultimate episode is pretty disheartening:(Mildred wearily arrives at the castle doors and finds Maude there waiting for her looking less than pleased)
Mildred: (hopeful) Maude.
Maude: (flatly) Mildred.
Mildred: Sorry....you were right..please don't be mad at me.
Maud: .... (sing-song) MISS HAAAARDDBROOOM!
Mildred: (shocked) Maude!
Miss Hardbroom: (appears from thin air and glares angrily at Mildred) Did you leave school grounds without permission?
Maud: (Equally pissed) She did, Miss Hardbroom.
Mildred: I....I know, but...
Miss Hardbroom: You know the penalty (expulsion). I transfer you home immediately.
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