The situation in general: Chloé, in an attempt to further bully Marinette, steals her Miraculous, thinking they're just earrings. She proceeds to keep them, becoming the Nominal Hero Scarlet Lady who is adored by the public while doing little to none of the heavy lifting in fighting akumas.
One of the bonus strips shows Adrien looking sparkly-eyed and excited to be a superhero, unaware that he'll soon be saddled with an Alpha Bitch partner who takes all the credit for his victories. After only a couple of chapters, he's been left burnt out dealing with the mess on his own.
Tikki's situation, as she's stuck with an owner who has no inclination to be a real superhero while being left to mournfully watch her mistreat Marinette, her actual intended owner. Furthermore, as the series goes on, Chloé becomes even more egotistical and sociopathic: while Nooroo is used by Gabriel for the sympathetic reason of wanting to save his beloved wife, Tikki is stuck with a Jerkass who's only interested in being a hero for the fame and glory.
At the end of "The Bubbler," Chloé hits Sabrina in the head with the latter's own tablet simply for telling her that Adrien's present will be delivered late. Not only does this leave a huge bump on Sabrina's head, but the poor girl notes that this kind of violent behavior is becoming increasingly common for Chloé.
Théo Barbot gets his heart broken twice in "Copycat": first when Scarlet Lady cruelly rejects him, then again when he realizes what she's really like.
Sabrina being genuinely worried about Chloé in "Horrificator" and desperate to find her friend despite the danger. What's sadder is how misguided her loyalty is: had their roles been switched, Chloé probably wouldn't have spared Sabrina a second thought.
Marinette's eyes are red when she finally exits the limo at city hall, showing she had cried over Chloé's seeming fall to her death.
André's utterly devastated face when Rogercop implies he killed Chloé. As many defects as the man has, it's clear he loves his daughter. He doesn't recover until Scarlet Lady tells him that she "saved" Chloé, and even after she returns in her civilian identity, Chloé completely ignores her father in favor of her purse and bracelet (despite having just seen how badly he had taken her apparent death).
Sabrina has Dull Eyes of Unhappiness throughout "Darkblade," showing she still isn't over how her father was fired because of her "best friend." She then cries tears of guilt when Sabine tries to cheer her up with a free bag of cookies while Sabrina's trying to sneak into the woman's daughter's room for blackmail material.
Lila gets utterly humiliated and thrown into a fountain in the middle of winter by a vengeful Scarlet Lady in front of not only Adrien, but also her other classmates. To add insult to injury, she also catches a cold.
Adrien barely even reacts to the high likelihood that his own father is Hawkmoth. It really shows how jaded he's become if a major revelation like this hardly even phases him.
Tikki looks out wistfully from Chloé's purse as Marinette receives her Kwagatama, thinking, "Bon anniversaire, Marinette." Meanwhile, though Marinette adores it, she's completely oblivious to its significance. The author's note says, "I'm not crying. YOU'RE crying!"
During "Evillustrator," Chat Noir, after having to save Marinette and himself following a claustrophobic breakdown, hugs her and practically begs her to not participate in anymore akuma fights out of fear for her safety. Marinette is so stunned by Chat's Moment of Weakness, she can't help but agree to try.
"Vanisher":
A flashback reveals what led to Sabrina's akumatization into the titular villain: Chloé, upset at being contradicted on television twice by Sabrina and in front of Jagged Stone (who adds to her humiliation by pointing out she nearly gave him food poisoning and got him turned into an akuma's minion to Nadja), steals the hat she let Sabrina "borrow" in exchange for doing her share of a physics project and declares that their friendship is over and that Sabrina should just disappear. No wonder Sabrina got akumatized almost immediately afterwards.
When Marigold goes for the traditional Fist Bump from canon, Chat... doesn't reciprocate his new ally's gesture. He professionally thanks her for the help and then leaves, leaving Marigold shocked and saddened. While it's expected of Chat to be wary of new help given his bad experiences with Scarlet Lady and Volpina, it still hurts considering it's Marinette under the mask.
A downplayed and possibly unintentional example on the header picture for "Riposte." Kagami is crouching and holding her hand out with a sad expression on her face. It makes you want to give the poor girl a hug.
Sabrina admits she's still getting used to no longer being friends with Chloé. Even though she's long already wised up to the true nature of their "friendship," it's clear cutting off ties with Chloé has negatively affected her.
Speaking of Ondine, she doesn't even get a break in "Dark Cupid." Kim is waiting on a public bridge to give her the gift, only for Chloé to walk past and, thinking that the gift is for her, proceed to reject him, causing Ondine, who was walking towards them, to think that Kim's present was for Chloé and not her. Chloé ends up preventing Kim from getting a word in, leading to Ondine running off in tears and Kim getting akumatized over a completely avoidable misunderstanding.
At the end of "Intermission," Marigold and Chat Noir reflect upon how Tikki, much like Nooroo, is stuck working with somebody who likely sees her as nothing more as a means to their own selfish ends. Chat Noir notes that Plagg has suggested Tikki will prioritize Nooroo's safety over her own, and all Marigold can do is note how unfair it all seems.
On the other hand, to wield her true Miraculous, Marinette might have to give up Pollen despite the genuine friendship they've formed, with the Kwami not having been this well cared-for in years.
Tikki gets inadvertently sling-shotted out of Chloé's purse into the escape car while Kagami's preventing the latter from entering. The Kwami is later shown shivering on the floor as the car gets gassed, weakly whimpering Chloé's name, sick, suffering, and completely helpless.
After Marinette recovers her and brings her to Master Fu to be healed, Tikki gets to share a hug with the person she knows is her true bearer, but due to the rules, she is not allowed to tell Marinette that. Needless to say, Tikki ends up crying a little.
Chloé being legitimately, if overdramatically, upset when Adrien cuts off their friendship after one too many of her stunts, with her tears flowing out like a waterfall. Of course, by the end of the chapter, she takes the I Reject Your Reality approach, decides he's the one who's being dramatic, and forgives him, which, when you think about it, is sad all by itself.
The events of "Despair Bear" have damaged, if not outright shattered, Scarlet Lady's (undeserved) image as a beloved superhero. Good news for the heroes who need her reputation smashed before they can get the Ladybug Miraculous away from her. Bad news for all the people who have had their misguided view of their superhero ruined, especially Alya, her biggest supporter, who can't even respond when Marinette tries to ask her something and has to take time to process what she's seen.
Even though it's entirely her own fault, it's still saddening to see Chloé's selfishness and complete Lack of Empathy slowly but surely ruin her friendships with Sabrina and Adrien. The worst part is that she's simply too self-absorbed to notice or care that she's lost the only two people in all of Paris besides her own father who could actually tolerate her.
Kagami's mother reveals in "Ikari Gozen" that all her friends abandoned her after she became blind—that's why she doesn't want Kagami to have friends.
The Reveal that the reason Anarka and Jagged Stone broke up was because Bob Roth faked a pair of Dear John Lettersafter Anarka told Bob that she was pregnant. While the couple's reactions to this is Played for Laughs, it's sad to learn that Anarka and Jagged lost a good relationship and that Luka and Juleka grew up without a father all because of one man's greed. Even after the two reconcile, Jagged openly admits that there's practically no chance things can go back to the way they were before.
Marigold's despair at getting everyone caught in "Robostus," saying she's sorry when she's about to lose her Miraculous.
While it was kind of her fault, it's a little hard to watch Nadja break down in tears after the disastrous interview in "Prime Queen," especially since the producers were the ones who pushed her into being invasive with the questions. Meanwhile, Marigold looks heartbroken because she had kissed Chat Noir, and not only does she not remember it, but Chat Noir states it meant nothing because he only did it because of the akuma. Chat Noir realizes a bit too late that he hurt his partner with that statement. It gets even worse when Marigold admits her true feelings on live TV when Nadja turns into Prime Queen, and when Chat initially thinks she's lying, she says:
Marigold: Superheroes don't lie, Chaton. Chat Noir:[blushes in embarrassment]
While Mme. Bustier explains to Marinette that neither she nor Chloé are going to be punished in "Zombizou," Marinette sadly explains that she's already being punished since someone who stole her hard work isn't being properly punished for her actions while also getting the credit. It gets worse when Bustier starts giving her the "forgiveness" speech from canon, which finally hits the poor girl's Rage Breaking Point.
It gets worse when Bustier gets akumatized and targets Marinette because she couldn't handle her student calling her out on being an ineffective authority figure, driving home how the teacher responds to bullying by Blaming the Victim.
The end of the chapter makes it abundantly clear that Marinette's not the only one who's suffered because of Bustier's teaching methods—a number of other people in her class found themselves hurt by the teacher (largely her refusal to do anything about Chloé's behavior) but were afraid to speak up because of her reputation. Not only that, but they had to bottle it all up and keep it to themselves, wrongly thinking that nobody else understood them.
Ivan: If you mess up a little, she sends you to the principal. But I knew I'd look like the bad guy if I said anything negative about the "nice" teacher.
It's really sad and bittersweet to see the kids complain about Bustier's methods when the episode started with them all bringing her birthday presents.
While Chloé is even worse than she was in canon, she's clearly hurt when Sabrina tells everyone that her own mother forgets her birthday.
After Alya falls to one of Zombizou's zombies and Nino stays behind with her, Marinette breaks down crying, wondering why her friends didn't try to protect themselves and chose instead to sacrifice themselves to protect her, which becomes worse when Chat Noir (who had just declared his intention to keep her safe) gets infected while trying to protect her from Scarlet Lady.
After defeating Zombizou, Marigold falls on to Chat's chest, crying after the whole distressing experience.
It's a bit sad when Mme. Bustier thanks Scarlet Lady for being Chloé's best friend and thus not leaving alone, unaware that Chloé really is alone due to being Scarlet Lady. It really drives home how Chloé has, by her own actions, driven away nearly every person who had cared for her just a few months before.
It should be pointed out that the reason Bustier says this is because she believes that Chloé's friends note Adrien and Sabrina are being unnecessarily mean to the girl currently. And by "mean," she's referring to how they cut off their toxic relationships with Chloé and want nothing to do with her due to Chloé's own actions, showing just how completely in the darkthe teacher is to the actual situation.
Not only that, but this comes right after the heroes had explained to the teacher that negative feelings are perfectly normal and nothing to be ashamed of, showing it was an Ignored Aesop for Bustier. She has a long way to go before she finally understands that her class's dislike of Chloé is justified, assuming she ever does.
This post on zoe-oneesama's page helps to make it clear that it's teachers like Bustier and many of adults in general who are responsible for people like Chloégetting away with what they do and thus destroying the faith people may have in authority figures to help if problems are brought to their attention. In addition, a brief line at the end of the post more or less states Sabrina's relationship with her father has suffered due to the man being oblivious to how his daughter was being used for years despite being a police officer.
Much like the original episode of "The Mime," Marinette accidentally erases a video Alya took and had planned to post for the blog and in a panic decides to steal Alya's phone to try and somehow fix her mistake. The difference this time is that Mylène is still around and calls her out for her theft, prompting Marinette to breakdown and reveal her insecurities: she fears her mistake will drive Alya away and therefore drive everyone else away because no one was friends with her until Alya stood up to Chloé for her. It does turn heartwarming afterwards, with Mylène, who's usually among the more emotional and nervous members of the class, being the one to comfort Marinette and suggest a solution. However, it's still really sad that Marinette thinks so lowly of herself despite how often it's shown that her classmates and friends love and support her. It'll take a long time for the trauma she endured from Chloé's many years of bullying to fully heal, assuming it ever does.
When André Bourgeois invites Chloé to a screening of his film, she gives a Blunt "No" before slamming the door in his face, all without even sparing him a glance.
The ending of "Gorizilla" highlights the emotional distance between Gabriel and his son, with Adrien flat out telling his father that he's never given Adrien a reason to trust him.
The various nightmares shown in "Sandboy" tend to be this:
Marigold's nightmare is becoming powerless—a clear sign of how much the events from "Zombizou" (in which all of her friends slowly got infected by the akuma while she was unable to transform) are still weighing on her mind.
Meanwhile, Chat Noir's fear is Marinette being akumatized. Not only that, but it's implied it happened because he wasn't there to prevent it.
"Reverser" is caused by Marc and Nathaniel meeting up... only for Chloé to angrily barge in to defend the "slander" against her "BFF" Scarlet Lady and tear up Marc's book right in front of them before ranting at Nathaniel (she only stops when the akuma shows up).
The end of "Reverser" reveals Pollen already knows that Tikki was meant to be with Marinette instead of her... so if things go back to how they were meant to be (which seems very likely at this point), Pollen will probably have to say goodbye to the Queen she loves so much. Pollen has already quietly and sadly accepted this, but she can't even tell her beloved Queen about it.
"Party Crasher" makes Wayhem's akumatization much more sympathetic; when he's drawn to the manor by all the ruckus, he thinks Adrien lied to him when he claimed that he'd be busy earlier, as well as when he said that he wanted to introduce Wayhem to all of his friends. Naturally, Hawkmoth takes advantage of this in a bid to restore power to his lair. The situation also doesn't get resolved on-panel, as Wayhem disappears after being dealt with. Meaning that as far as the audience knows, he never learns it was all a misunderstanding.
While Philippe's antics in "Frozer" to find students for his skating classes are quite funny, it bears repeating that the only reason for them is that he's desperate to keep his skating rink open against the predations of the mayor, who is quite willing to ruin one person's living because of his daughter's greedy demands for a gym—which she only made because she was jealous of Adrien and Marinette going out on a date at the rink. When Philippe accidentally hurts Marinette in his haste to accost Adrien, he's clearly horrified by what happened, and just to twist the knife, André, the one who's putting him under all this pressure in the first place, sanctimoniously scolds him, acting as though he played no part in causing it.
Clara is clearly devastated when the video shoot she had planned so much for is suddenly shut down by the mayor for seemingly no reason at all.
After Frightningale is defeated, Sabrina briefly refers to herself as a sidekick before Marigold corrects her and tells her she was a hero and partner. The comic doesn't focus on this much, but it's clear that the years Sabrina spent as Chloé's lackey is still affecting how she thinks of herself and that it'll take a long time before she completely overcomes that mentality.
In the bonus image for when Clara is akumatized, two people are shown being frozen, devastating their (girl)friends:
Kagami is shown telling Aurore to run just before being frozen while Mireille tries to pull her friend away from danger.
Juleka clearly attempted to protect Rose, as she's become a statue as well while poised as a Human Shield. But Rose still got hit, and she's clearly crying for her girlfriend as she begins to sing "I Love Unicorns" in an attempt to avoid sharing the same fate.
In "Malediktator", Zoé comes to Paris with Audrey and attends school with Chloé. In an attempt to fit in with her half-sister, she makes fun of Alix's presentation, causing most of the class to believe that she's just like Chloé. The look on her face during this reaction says it all.
When Zoé first comes to Paris, Chloé actually seems to warm up to her and takes her under her wing (in her own twisted way). She brings her half-sister to school and honestly seems to be enjoying her company, clearly (and unbeknownst to her) in need of company after having driven away her two closest friends. Then, Zoé admits she doesn't know who Scarlet Lady is and instantly loses Chloé's goodwill, with the latter throwing a tantrum and demanding her half-sister leave when all she could have done was explain who the heroine is. It's sad for both Zoé, who wanted to meet her sister and get to know her, and for Chloé, whose inability to learn from her mistakes costs her yet another companion.
While Chloé ultimately "forgives" Zoé for her slight after Malediktator because of how much Zoé ends up gushing about Scarlet Lady, it's implied that Zoé is faking her admiration for the wayward heroine just to get back into her sister's good graces. It's quite sad for not only Zoé, who is implied to have learned to fake her personality as a means of fitting in with her family, but also Chloé, who seems genuinely touched by how enthused her sister is towards her masked self.
André discovers all of a sudden that Chloé intends to leave for New York because he doesn't have enough authority as mayor to close her school and banish Zoé from Paris. While Audrey indifferently keeps talking with (and berating) her employees, he futilely begs his daughter—who, regardless everything she's pulled, is still the only family he still has—to stay, crying out a Big "NO!" when his pleading fails. And, of course, on top of that, Hawkmoth moves to make it even worse by akumatizing him.
Additionally, as he's beseeching Chloé, André insists that they can work things out with her sister, heavily implying he sincerely wanted his daughter and stepdaughter to get along and is crushed that it seemingly won't be happening now.
Meanwhile, Zoé isn't seen anywhere as Chloé gets in the helicopter with her mother. Audrey is later revealed to not have been paying attention and thus unaware that Chloé planned on taking her to the airport so they could go back to New York when she dragged Audrey into the helicopter, instead thinking they were on their way to her office in Paris. Still, it's quite shocking that she cares so little about her daughters that she may have flown all the way back to New York without her daughter Zoé.
When Chloé announces that she's leaving Paris forever, the entire school breaks out in celebration, only for it to come to a complete halt when Zoé shows up asking what the party's for. One person even laments, "Oh... She's still here." This shows that due to her sister's actions, Zoé has a lot of work ahead if she wants to improve her own image.
The fact that it's implied that Marinette said it tells a lot.
Malediktator himself is a sad akuma, seeing as his first action is to make Audrey dedicated to their family. Even as a villain, André really just wants a normal family.
At the beginning of "Queen Wasp", Gabriel makes the uncharacteristic step of hugging Adrien in public while crying, which Adrien thinks is because his father was afraid of losing him to Style Queen... when the actual reason Gabriel's crying is because he's frustrated Style Queen failed. If the previous episodes weren't enough to prove that Gabriel is a horrible person, this is proof enough.
Chloé's reaction to her mother praising Marinette's hat in "Queen Wasp" certainly counts:
Previous episodes had established that Chloé has idolized her mother for a long time and constantly tries to get her mother's respect, only for Audrey to rebuff her each time. It's no wonder she hits her Rage Breaking Point when Marinette manages to earn Audrey's respect and even praise so quickly.
The fact that Audrey goes as far as to invite Marinette to work for her in New York upsets Chloé in particular. As Chloé protests, Audrey has never taken her to New York at all, yet she's willing to extend such a generous invitation to a complete stranger. Anyone would be upset in her position.
Chloé is clearly fighting back tears as she tries to convince her mother that she's just as exceptional as Marinette.
While Audrey isn't entirely wrong, she's extremely callous when dismissing the idea of Chloé being exceptional in any way, showing just why Chloé is so desperate for her mom's approval. It gets sadder when you realize that with the path Chloé's on right now, she has virtually no chance of ever earning her mother's respect.
Chloé's relationship with her mom is so bad that even when Audrey berates and cites several of her recent failures, Chloé is just happy that her mom noticed her.
When it finally does sink in that her mother doesn't consider her exceptional, Chloé's so desperate for Audrey's approval that she transforms into Scarlet Lady in public... which Audrey isn't at all impressed by, meaning Chloé outing herself was All for Nothing.
As satisfying it is to watch the entire city turn against Chloé after she outs herself, her reaction is this when you take everything into consideration. Despite being told both as Scarlet Lady and Chloé how everyone hates her, Chloé still runs around acting like people will fall over for a chance to be in her presence. Even when called out by Alya and the public to hand over her Miraculous to Chat Noir and Marigold, Chloé's reaction isn't tears over her lost celebrity but anger and a childish "Whateveeeeeeer!" at the mob for rightfully calling her out. Chloé's belief in herself as a beloved superhero has reached the point of full-on delusion that contradicts with how reality really is.
After this, Zoé makes the unwise decision to suggest that her sister just drop the hero stint and give the earrings to Marigold, misguidedly trying to help her sister move on. Unfortunately, Chloé interprets her advice as a betrayal and has a full Villainous Breakdown, throwing her Miraculous at Zoé; screaming that she hates her, Paris, and especially Marigold; condemning them all as "traitors"; and slamming her bedroom door in her half-sister's face before collapsing onto the floor on the verge of tears. To make matters worse, an akuma flies in, ready to transform her.
As noted by the author, Chloé, in spite of all of her attempts to reject reality, was actually starting to realize how wrong things have gone, and she mentally latched on to Zoé as her Living Emotional Crutch, seeing her sister as the one person she was certain would love her unconditionally—only to mistakenly perceive Zoé's attempts at helping her move on as a betrayal of their sisterly bond, finally convincing her that she's truly on her own (even if she has yet to realize that it's all down to her own behavior).
The author adds that considering just how many people have failed Chloé for her to reach her lowest point, it's hard not to describe her Villainous Breakdown as tragic.
And the most tragic part of it all? Chloé completely fails to understand just what led her to this point in her life, assuming that everyone was just hating on her for no reason. For most characters, this would be the moment where they'd have a Heel Realization and, if not start trying to better themselves, at least realize they were the only one to blame for their own misery. Chloé just goes full Never My Fault mode, refusing to see herself as anything but the victim.
After Queen Wasp is defeated, Nadja's eager to milk the drama for all it's worth, calling up Audrey on her tablet for a remote interview... which she's staging right in front of Chloé, with a camera trained right on the disgraced heroine to record her reaction to hearing what her mother has to say. Chloé's Tantrum Throwing may be par for the course, but given how the reporter was aiming to exploit her emotional breakdown, it's hard to blame her for that particular aspect of her outburst.
In the aftermath, Zoé confesses to Marinette how she feels that everything she's done to try and connect with her neglectful mother was All for Nothing:
Zoé: You're lucky, Marinette. Your parents are so invested in your life and dreams. Marinette: ...I know. Zoé: I've spent so much time trying to remind my mother that she has daughters. I played the part, acting just like her. I guess Chloé had the same idea, only she wasn't acting. All to get a scrap of Mom's attention. (breaking down into tears) Now I don't even know how to be myself, and Chloé just is a terrible person! And Mom still doesn't care about us! It's so... unfair!
Plagg notices Adrien is downcast in the aftermath: as Adrien puts it, he's been in the same place as Chloé, futilely trying to gain their parent's attention - but, as he points out, all the terrible stuff Chloé did wasn't because of her desire to imitate her mother, but because she wanted to. While he did cut ties off with Chloé, it's clear he still remembers his friend and is barely able to reconcile that image with the current Chloé.
Downplayed. Although Marinette has finally received the Ladybug Miraculous and even gets to keep Pollen as well, she can never be Marigold again, marking the End of an Era.
In "Catalyst", Nathalie creates an illusion of an akumaized Chat Blanc vaporizing Marigold with cataclysm, which quickly drives the watching people into despair and panic.
The two that really drive it home are Alix's and Kim's.
As Zoé and Lila try to rally their classmates to resist Scarlet Moth, Alix apologizes because she's actually really freaking scared, and she ends up transformed into Timebreaker.
Kim calls Ondine, who is seen crying as she informs him that there are a lot of Akumas around and Kagami already turned. The last thing Kim hears is Ondine screaming at an Akuma to stay away, which causes Kim to become Akumatized as well.
on zoe-oneesama's page helps to make it clear that it's teachers like Bustier and many of adults in general who are responsible for people like Chloé getting away with what they do and thus destroying the faith people may have in authority figures to help if problems are brought to their attention. In addition, a brief line at the end of the post more or less states Sabrina's relationship with her father has suffered due to the man being oblivious to how his daughter was being used for years despite being a police officer.