* DracoInLeatherPants:
** Hugo was shown to be a very bad person practically from the first episode he appeared in, yet he has been regarded as one of the most attractive guys in the series.
** Jacques Noiret is also a good example. He was cruel to his son and to Elsa when she was his girlfriend, but several girls and women like him. His eleventh-hour HeelFaceTurn didn't help matters.
** Nicolás Garrido became this quite soon: he was quite a {{Jerkass}} at the start, yet everyone was hoping that he came into the school and hooked up with Elsa. Even after discovering he was into the plan to kill everyone inside the school people still liked him.
* EnsembleDarkhorse:
** Fermín, the school's cook, who was only intended to be a background character at the start of the series, but when he started to gain popularity he was turned into a spy that had been sent into the school to discover the BigBad's plans, as well as finding many objects [[spoiler:that had been stolen from Jewish people during UsefulNotes/WorldWarII]].
** Julia, entering the school in the 2nd season, was nearly from the start a popular character with her attitude and very happy disposition.
* FridgeBrilliance: In the last episode, Héctor asks about Elsa - who had been his girlfriend of years and wife for a few months, but whom he had broken up with after learning she had cheaten on him with his best friend - but doesn't say a thing about Lucía - who had been his girlfriend for the last months before the summer. Many fans wondered why, but then the brilliance struck: since he was hidden in the basements and Lucía would have been in charge of his healing, then he would have realised that she was part of the bad guys.
* GermansLoveDavidHasselhoff: It's getting a good reception in many other countries, such as Italy or Japan.
* SugarWiki/HeartwarmingMoments:
** Every kiss between Marcos and Carol. Every single one of them.
** When Marcos learns that Héctor [[spoiler:is actually his uncle]], the two share one of this.
** Iván and Julia's reconciliation [[spoiler:after Iván broke up with her so that she wouldn't have to take care of him since he has Alzheimer]].
** When, after more than 30 years of separation, [[spoiler:Héctor finally meets with his sister Sandra]].
* HesJustHiding:
** When [[spoiler:Héctor]] died, many fans thought that he was still alive and his death was only simulated. They were right.
** Also thought about [[spoiler:Carol]], because few could believe that her character, one of the favourites of the audience, would actually die. This time, they were wrong.
** In-universe example: the bad guys [[spoiler:were Nazis and]] had simulated their deaths in the past to avoid being caught.
* SugarWiki/MomentOfAwesome:
** Iván saving Julia by smashing her former lover's car's window with a motorcycle helmet.
** Iván fighting Shotokan-style against Hugo. The last time they do it while the school is burning. Iván wins.
** Vicky knocking [[spoiler:Amaia]] out with a shovel.
* MoralEventHorizon:
** Jacques Noiret happily letting Iván getting infected with TheVirus so that he doesn't interfere in his plans and blackmailing him so that he tells him where María is.
** [[spoiler:Roque]] reaches this when he hits [[spoiler:Carol]] and makes her fall down a very tall tower, then burying her instead of checking whether she is alive. When he later gets a call from her mobile phone he doesn't tell the others, he distracts his friends so that he can reach Carol first and when he finds her the only reason he doesn't kill her is because [[spoiler:Marcos]] arrives there on time. Sadly, it wasn't soon enough to prevent her death.
** Ritter Wulf [[spoiler:when he created TheVirus and started to experiment on the prisoners of the Belzec extermination camp]].
* NauseaFuel:
** When Héctor [[spoiler:discovers the corpses of his old orphanage friends in the middle of the forest]].
** The "home videos" with the experiments on the orphans back in the 50s-70s (also qualify as NightmareFuel).
* NightmareFuel:
** The eyes in the bottle... god, the eyes...
** Also Paula's eyes [[spoiler:when they suddenly start to emit light in the middle of the night]].
** Julia's encounters with the ghosts are this for her. The creepiest one is when she meets Eva's ghost... at the same moment [[IdenticalGrandson Paula passes near the ghost]].
* RetroactiveRecognition:
** A rare inversion -- some viewers might best recognize Jacques Noiret's actor, Carlos Leal, as the same actor who plays the croupier at the poker tournament in ''Film/CasinoRoyale2006'', but his appearance in ''Casino Royale'' was a year ''before'' this series began.
** Some viewers will also recognize Carol, who's played by Creator/AnaDeArmas, now best known for ''Film/{{Knock Knock|2015}}'' and ''Film/BladeRunner2049''.
* {{Shipping}}:
** Almost from the start, people wanted Marcos and Carol to hook up. It would take nearly 5 seasons for that to happen. [[spoiler:And then Carol died.]]
** Iván and Julia would become one of the fans' favourite couples.
** Starting with the 3rd season, many fans were divided between those that wanted Marcos and Carol to be together and those that wanted him to be with Amelia. Even after knowing that [[spoiler:[[FanDumb Amelia was part of the bad guys]]]]. Amaia in the 6th and 7th season would also become a part of this war. [[spoiler:In the moment she was revealed to be the grand-daughter of one of the bad guys and TheMole, everything changed.]]
* TearJerker:
** [[spoiler:Cayetano's death]] in between the 1st and 2nd season.
** Most fights [[spoiler:between Iván and Julia]] and [[spoiler:Marcos and Carol]].
** The Gnome ([[spoiler:Elsa's twin brother whom she had never known was alive]]) dying when the police shoot at him.
** [[spoiler:Nacho's death from TheVirus and having to leave his body behind so that they don't get caught by the bad guys]] in the 5th season.
** [[spoiler:Carolina's death]] was one of the biggest in the whole series, and made everyone sad, especially [[spoiler:when Carol dies in Marcos' arms, considering that the last thing they had done was to fight]]. Compounded when [[spoiler:a few days later, in the anniversary of their first kiss, Marcos gets a bottle of wine with a letter from Carol forgiving him for the fights they have gotten into, and Marcos has a flashback to the happiest day of his life, when he and Carol made love in the pigeon house]].
** [[spoiler:Elsa's death from TheVirus]], with only Jacinta, who had hated her for most of the series, making her company (not that she wasn't beloved, she just didn't want people to know that she was dying).
** [[spoiler:Fermín's death]] just when everyone was healed and saved from death, also [[spoiler:in the arms of his beloved, María]].
* TooCoolToLive: Fermín. He certainly was the biggest badass of the series, the greatest hero... and he gets stabbed by Garrido in the last episode, dying in María's embrace.