- Alas, Poor Scrappy: Ellen's death.
- Also toyed with when the death of Nathan's daughter was probably one of the few rare times the audience felt any sympathy for him.
- Big-Lipped Alligator Moment: Tends to happen in the more recent series, from 2007-2008 onwards.
- Bizarro Episode: Almost once a series this happens.
- Ear Worm: Woe betide you if you live in Britain and you can't hum the Theme Tune.
- Ensemble Dark Horse: Charlie Fairhead, who went from playing hockey in the corridors to becoming, by Word of God, the show's most important character.
- Big Mac.
- Connie Beauchamp, who enjoyed similar popularity during her time on sister show Holby City. Fan reaction when it was announced that she would become a regular on Casualty almost four years after her last Holby City appearance can best be described as rapturous.
- A blonde nurse, only ever referred to as "Cath" or "Kath", seems to be popular with the fans, yet never really gets any storylines (not even a minor one). She's not a One-Shot Character or a Ghost Extra by any means, but she rarely speaks. But, amazingly, she is never credited on-screen. She is blonde and appears mostly in scenes where Zoe, Ruth, Jay and/or Nick Jordan are present.
- Genius Bonus: In one episode, a dispatch with a Scottish accent sends Nikki and Comfort to St. Aloysius' Church. St. Aloysius College is a well-known Catholic independent school in Glasgow.
- Heartwarming Moment: Downplayed a little. Patrick, after his and Lara's moment gets killed again.Max: Lara, I need you. (she leaves).Patrick: You're not the only one, Max.
- Hilarious in Hindsight: Charlie and Baz's Ross-and-Rachel like relationship is compounded by having Baz briefly date a posh bloke called Charles for one episode. Charlie suggesting that they be "friends who sleep together sometimes" could also be likenened to the episode where Monica and Richard try to be friends.
- Les Yay: Selena and Maggie.
- They Changed It, Now It Sucks!: The Retool seems to have resulted in this in the opinion of some fans. You only have to look at the ratings to see that it's not what it was.
- What an Idiot!: Guppy snorting some heroin he stole from a patient because he thought it was cocaine.
- WTH, Casting Agency?: Charlie Brooker criticised the series for casting painfully soft-looking middle-class actors as working class youths.
- The Woobie: Dr. Ruth Winters. Something of a Dr. Jerk who alienates everyone around her, always puts her career first and has lied to cover up her mistakes, several of which have led to patient deaths. And yet...her father was a manipulative alcoholic, her mother committed suicide and her brother is a drug addict. After a patient dies due to her misdiagnosis, she tries to hang herself, fails and ends up in a coma. After recovering from that, she sleeps with her boss, who rejects her the next day. She begins seeing a nurse, Jay, but a senior doctor tells her she should end it for the sake of her career. She gets pregnant by Jay, but terminates the pregnancy without telling him and they fall out after she cancels a date. She haemorrhages and is taken to hospital where, humiliatingly, she is treated by her own colleagues and has to tell them about her pregnancy. She lies to Jay that she had a miscarriage and reluctantly ends their relationship. Her brother, fresh out of prison, emotionally blackmails her into letting him stay over Christmas. He steals from her and runs off and she goes on a nightmare journey into an underworld of drug addicts and male prostitutes in an effort to find him. She confides in Jay about the crappy time she's having and they briefly reconnect, but he walks away when she tells him about the termination, despite her finally finding the courage to tell him she loves him. Months later, she gives a terrible presentation at a medical conference but a high-profile doctor takes an interest in her and she ends up marrying him, Jay's declaration of undying love for her coming too late to stop the wedding. Ruth realises that a) she still has feelings for Jay but he has begun seeing someone else and b) that her new husband is gay. They continue with the sham marriage for the sake of both their careers but then her husband's boyfriend, whom he had agreed to stop seeing, begins working alongside her. This does not go well, and her husband eventually leaves her for his lover, ruining another Christmas. Subsequent to that she mistakenly accuses a man of raping her, almost wrecking his marriage, and, after suffering a nervous breakdown, she is sectioned and found to be bipolar. Her storyline has a happy ending, in that she reunites with Jay and they drive off together into the sunset, but she certainly earns it.
YMMV / Casualty