- David in general even when viewers first watch the show knowing that he's not (entirely) crazy makes this series the incarnation of Unreliable Narrator.
- He spends the majority of his life haunted by The Devil with the Yellow Eyes, who appears most frequently when David is about to lose control of his powers. It makes you wonder whether or not it's entirely his fault.
- Even after learning that he's not crazy, his lifelong traumas, his difficulty controlling his mutant abilities, and hints that at least some of his problems are psychological in nature, constantly make you question everything that's happening whenever he's on screen.
- The above two examples become even Harsher in Hindsight as of the season 2 finale, which confirms that while they are true to an extent, his own confirmed mental illness on top of his powers and his past really makes the verdict about his sanity nigh impossible to pin down.
- In this Alternate Timeline separate from the X-Men films, mutants appear to not be as common knowledge as other movies have portrayed them. On the one hand, this means that they're not persecuted by the public, but this also means that they're more likely to be blamed for things that can't be explained, believed to be mentally ill (like David or Syd), or worse, are the victims of a sinister Government Conspiracy.
- The final paragraph of the released first page of the Episode 9 script:
- "He starts to laugh too. They laugh longer and harder than seems normal, until it reaches the point of hysteria.We see their faces in close-up, the panic and grief and disbelief at the reality they're in. They would scream if they could, but they can't—so they just laugh and laugh."
- The recent announcement that the upcoming Season 3 would be the last series of Legion, which has deeply saddened fans of the show.
- Watching David attempt to hang himself, especially with hindsight and observing the Shadow King lingering in the background.
- Even though we didn't get to know her too well, David (in Syd's body) finding Lenny's corpse fused with the wall is depressing to watch, especially since she appeared to be the Only Friend David had.
- David's on the verge of tears when he tells Melanie and Ptonomy that his father had passed away last year, and he didn't get the chance to say goodbye because he was institutionalized at Clockworks.
- David's pitiful existence as a junkie before his institutionalization.
- Amy is brutally tortured by Division 3 with absolutely no idea why and what all this has to do with David, and all David can do is watch from afar telepathically.
- The pervasive nature of the Shadow King's presence in even David's happier memories, and the way he makes David instantly forget his presence.
- The story of the poor woodcutter and his wife, which perfectly mirrors Melanie's sorrow over the missing Oliver. Told by Oliver's voice, to boot.
- It's rather low on the list of horrible tragedies in the show, but it's sad that when Cary was born after Kerry, their father abandoned their mother when he thought she was having an affair - when the truth was that they were a mutant Literal Split Personality.
- While in the ice cube, David mentions Melanie's name to Oliver, not knowing that Oliver is Melanie's missing husband. In response, Oliver says vaguely that he knew a Melanie once. He's been gone so long he forgot his own wife.
- David finding out from Amy that he is adopted. He is absolutely devastated by this reveal and actually has tears flowing down his eyes.
- The whole cast becomes trapped in some alternate world where they're all inmates and Lenny is their doctor. Melanie takes it especially hard, as Lenny delivers a Breaking Speech convincing her that her husband is truly dead and the whole "trapped in the astral plane" business is just a story she tells herself to avoid dealing with her grief. Melanie spends almost the entire rest of the episode nearly catatonic.
- David isn't any well off in the alternate Clockworks either, despite being relatively comfortable— in it, he inadvertently forms a rift between himself and Syd when he brushes off her observation about the bedroom door in the hallway; and Nurse!Amy tells him outright she and her family secretly hated him, and fake-gags loudly to emphasize it. That's before Psychiatrist!Lenny/TDWYE delivers his hybrid Breaking Speech-Motive Rant and traps him in a glass coffin.
- Ptonomy recounts to Lenny how his mother died. She dropped dead while doing the dishes one day. Just like that. While he was in the room. He was five. He tells it serenely, with a smile on his face, just like it was any other memory.
- It's also sad to see the pugilistic and headstrong Kerry become a shell of herself who is entirely dependent on Cary but can't phase with him. She doesn't even try to fight The Eye, but just runs away in terror.
- While David is figuring out why he was put up for adoption, he has a brief moment of self-doubt and questions whether it was to keep him safe from the Shadow King, or if his parents just didn't want him. In a blink-and-you'll-miss-it shot, Chalkboard Xavier reaches out his hand towards David in despair.
- Kerry gives Cary the cold shoulder after they escape from fake!Clockworks. It's clear that their relationship has suffered as a result of Cary's otherwise noble actions to help them escape, which left Kerry alone for a time to be tormented by The Eye.
- Oliver's fate. He finally breaks out of his prison in the Astral Plane and starts to remember Melanie, but is possessed by Farouk shortly afterward.
- Clark's recounting of what his life was and is like as a burn victim. About forty percent of his body is burned. He had a tube stuck in his urethra for weeks. His husband cries himself to sleep every night. Despite all the lofty field-work he once did, he's having to beg for desk duty. The show does an excellent job of generating sympathy for a seemingly one-note villain.
- Oliver laughing mirthlessly as he "enjoys" his state as a mental slave of Amahl Farouk.
- Melanie, broken after Oliver's and David's fates last season, is now a junkie, addicted to the same drug that David was before his institutionalization.
- The excellently-told metaphor concerning delusions. Incredibly sad that, as powerful as the human mind is, it's also so frail as to so easily descend into madness. Poor Albert A, and his missing leg.
- What Farouk!Oliver does to Kerry and Cary, especially after we see them so happy and coexisting.
- Melanie's speech to David about how his power is preventing him from being truly happy, and how the positive and powerful Summerland was worthless. It's especially sad coming from her since she was so caring and affirming toward David in the past.
- Despite the humor present, Kerry essentially has to be toilet-trained and taught how to eat and drink.
- Lenny's predicament. Farouk refuses to let her go, and even mocks her stated reason for leaving to David. She tells David that she pulled all her hair out of frustration, and tries to kill herself while he's there. Even if she were to leave, she likely would end up either back in an asylum or with a nose-full of drugs.
- The opening scene where Syd refuses to touch her mother as a baby and young girl. All set to a melancholy Bon Iver piece.
- Seeing everything that Syd had to endure while growing up. She had a intense fear of touch since birth and was bullied by other girls during her school years because of her dislike of being touched and whatever happened to her biological father.
- After seeing the couple making out in the art museum, Syd goes home and plants a kiss on her reflection in the mirror.
- The heart-wrenching scene revealing that Syd cut herself as a child.
- The sex scene in that episode is sad beyond words. A cruel twist on budding teenage sexuality and Syd's desire to be touched leads to a horrific outcome and massive amounts of emotional trauma for everyone involved.
- Lenny's home life wasn't exactly the greatest. Her mom was a junkie, her dad was a pedophile, and her gran repeatedly gave her alcohol to drink while watching cartoons. When she was nine. She never had a chance.
- Lenny running through some of what she did to get high. Example: she once lured a man with the promise of oral sex, only for her pimp to extort him for money with a fake gun to where he's begging for his life. All so she can get high again.
- Oliver telling Farouk that his experiences with the Astral Plane and as his slave have made it to where he can't tell what's real anymore.
- David tells Lenny that, until Farouk left, he didn't truly understand the meaning of silence. Never was able to appreciate the ambiance of a room, or hear a heartbeat.
- Oliver seeing a vision of Melanie while he's talking about morality with the Shadow King, and the look on his face as he sees her.
- David's painful reaction to discovering that Farouk has murdered his sister and used her body to make Lenny corporeal again.
- Throughout the episode, we see the different ways that David's life could have turned out. In one of them, he uses his telepathy to become rich and powerful, but also loses his empathy. In another, he is homeless and even less in control of himself than usual. And in still another, he lives a seemingly stable life with a job, with Amy constantly reminding him to take his medicine, but is so frustrated at his dependency on her that he snaps anyway. The Family-Unfriendly Aesop seems to be that going to Clockwork was the only path forward for him, even though it also set in motion the events that led to Amy's death.
- Katie Aselton's acting really cements the dairy worker timeline. She puts a lot of worry and a heartbreaking hitch in her voice when she calls that David "silly". It's evident she constantly fears for him.
- Davids arrest in the timeline where hes a dairy worker. Hes clearly terrified the whole time, and his attempts to explain his situation to the officers are ignored. Amy tries to help him but gets cast aside and shoved over. After this David freaks out and kills the officers, only to end up getting shot in the back and either killed or paralysed. The scene has some painful Reality Subtext regarding the polices violent treatment of mentally ill people.
- The timeline where David is happily married with kids is incredibly sad, if only because he'll never be able to have that with Syd.
- David's heartbreaking response to Amy when she asks him why he won't let himself be happy. And this is in the "real" timeline."Because I'm sick."
- The later scene where we see Amy dropping David off at Clockworks. He is very unsure and does not at all really want to go. It's Amy that convinces him, telling him that he'll only be there for two weeks. We last see him being led off by two big orderlies, with her tearfully waving goodbye.
- The ending, where Oliver is made to subvert Melanie to Farouk's control against their wills.
- Syd and Kerry both pleading with a strung-out, drug-addicted Melanie to come back to work. Her conversation with Kerry is especially sad, as Melanie repeatedly questions what is real while Kerry looks very disturbed and eventually leaves after she tokes up again.
- Watching Melanie (possessed by Farouk) break Syd's faith in David.
- It's incredibly sad to hear her refer to David as "insane" and a "monster", seeing as how she was once his champion and support.
- On a related note, watching David start to give in to his dark feelings regarding Farouk and his revenge.
- When Oliver and Melanie are talking in the ice cube, they trail off for a second before quietly remembering that they helped Farouk, and are thus partly responsible for what ended up happening to David.
- Watching the heartbreaking conclusion to David and Syd's love story.
- It's hard not to feel bad for David, despite what he did to Syd. His mental state had been beaten so badly to the point where he can't even properly decipher whats good or bad.
- The time demons force Lenny to experience the birth, life, and death of her daughter in the space of a few minutes.
- Unable to cope with the loss of Salmon and Violet, Lenny kills herself. And thus David loses one of the last friends he still has.
- David's rampage results in the death of Clark, profound injury to Kerry, and the erasure of Syd's mind, among other atrocities. He has no choice but to go back and undo everything, because there is nothing that he could do from this point on that would redeem him.
- The Breaking Speech Past Farouk gives to David.Past Farouk: You know why you have failed? Because under all your anger, there is a baby. Scared. Small. Given away by his mother and father. A baby who is unloved, and knows that he is unloved.David: I'm a good person. I deserve love.Past Farouk: No, you don't.David: [screams]
- The last shot of David and Syd looking at the former's baby self before fading away from existence