A few seconds later, Miss Hardbroom runs into the girls looking suspicious (the pig above is actually Ethel):
Miss Hardbroom: Hold on a moment. You girls haven't seen any animals on your travels have you?
The girls all share a look
Maud: (In an overly sweet and innocent voice) Do you mean kittens, Miss Hardbroom?
Enid making the entire background of the stage fall on Ethel.
All of Miss Bat's scenes in "Alarms and Diversions", most notably the fire drill where she has an anxiety attack in front of the whole school...after the alarm has stopped.
From the same episode, Mildred dropping the bucket of water on Miss Hardbroom.
Miss Hardbroom: (through the bucket on her head) "There is no need to ask which pupil is responsible for this.
Mildred tries to shuffle across the courtyard, hoping to hide in the crowd
Miss Hardbroom: (still through the bucket) Mildred Hubble!
When Mr Hallow arrives at the school, Miss Drill and Miss Bat have a good look at him through the keyhole of the staff room. Miss Cackle catches them and says "I believe your classes are waiting for you, ladies". Once they've gone, she then bends down to look through the keyhole herself.
The girls are on a field trip and run into a group of Canadian boy scouts. The leader has a talk with Miss Drill in his cabin and asks who Miss Hardbroom is. Cut outside to HB...
Miss Hardbroom: "Maiden Aunt!?"
When the girls play a basketball game against another school, Maude at one point gets the ball and walks towards the basket with none of the other team stopping her and gets one in. Miss Cackle and Miss Hardbroom jump up cheering and clapping only for the girls to inform them that Maude scored in the other team's basket.
Earlier on during practice, Ethel proves quite disastrous at playing and the girls have a good laugh.
Ethel: And what do you think you're laughing at!
Drucilla: I think they're laughing at you Ethel.
Ethel: I know that!
The first episode has Miss Bat take offence to something Miss Hardbroom says and sulkily lock herself in the staff room cupboard. Not batting an eyelid, Miss Cackle picks up Miss Bat's bowl of milk (?) and casually brings it to the cupboard door for her.
In the school pantomime, Miss Hardbroom is playing the Fairy Godmother. Mildred's reaction when she sees her in the costume says it all.
Maude is playing the Wicked Stepmother and her introduction in the pantomime is materialising out of thin air like Miss Hardbroom does. And guess who Maude is dressed to resemble? We even get a quick shot of HB with an annoyed look on her face when this happens.
Add in how incredibly into the pantomime the Grand Wizard is ("that's not our Cinders!") and the entire episode is one big CMOF.
From "Let Them Eat Cake", Miss Hardbroom strolls into Mrs Cosey's tearoom. As soon as Miss Cackle hears her voice, she dives behind the couch and then pops her head up to say "I'm not here".
During his lecture in the Great Hall, Baz and Gaz use a spell to make the girls put their hands up and not be able to speak. Mildred attempts to stop it by flicking an eraser off a ruler at Merlin (who's casting it). Unfortunately she misses...and hits the Grand Wizard right in the eye.
In "The Witchy Hour" the girls are in the middle of a live radio show and Ethel turns the DJ into a frog. Miss Hardbroom immediately takes over...and is surprisingly talented on the radio. Oh and she refers to herself as "Hot Stuff Head Hardbroom".
Miss Drill organises a hiking trip with a stop by Cosey's tea room afterwards and Miss Cackle offers to come along.
Miss Drill: But it's a hill, Miss Cackle. A steep hill.
Miss Cackle: Yes, Miss Drill, I am familiar with hills.