Many adaptations follow the 1939 film's trend of adapting out Cathy II, Linton and Hareton - focusing only on the first generation and skipping straight from Cathy I's death to Heathcliff's (or, alternatively, keeping Heathcliff alive in the end).
The 1939 film includes an ending shot with Heathcliff and Cathy's ghosts wandering the moors Together in Death. No such sequence exists in the book, but many other adaptations include something similar in some way.
Sabrina the Teenage Witch has a gag where Sabrina zaps herself into the book and is then seen running around the moors calling out "Heathcliff!" over and over - which she doesn't do in the book, and is a scene in the film. She likewise wears a gown inspired by the 1939 film - which changes the time period the book is set in (and therefore the fashions).
Adaptations also follow the 1939 film's lead in having Heathcliff and Cathy spy on the Lintons when they're fully grown adults. In the book, they're still children when this happens, and Cathy is kept at the house partly to be given lessons on how to be a Proper Lady.
Other scholars have suggested that Nelly was secretly in love with Hindley - as she takes his death especially hard, was quite aloof towards his wife Frances and seems to care for Hareton as a Replacement Goldfish. The 1970 film went ahead and made this part of the story.
Was Mr. Earnshaw justified in his Parental Favoritism of poor orphaned Heathcliff over his two selfish, bratty biological children, or were Cathy and Hindley just typical rowdy kids who could have grown up to be better adults if they hadn't been treated as The Unfavorites?
Was Linton an outright bastard from the moment he appears, or could he have been reformed by not being brought up by his dad?
If we assume that Cathy I's ghost really does roam the moors, haunt Heathcliff and eventually cause his death, is she motivated by undying love for Heathcliff and longing for him to join her, or is she a vindictive spirit striving to save her daughter from Heathcliff's cruelty? Or both?
Are any of the book's narrators (Lockwood, Nelly, and others who recount off-page incidents) reliable or not?
Is Isabella looked on too cynically by the narrative? Yes she's young and naive, but she doesn't seem to be attracted to Heathcliff's bad boy tendencies as much as opting not to be prejudiced like her brother and sister-in-law and give Heathcliff a chance. He does go out of his way to seduce her, putting on a good show of being a gentleman - and he pursues her after Cathy tells him of her crush. He did his best to hide his bad qualities from her, and she was already feeling isolated after Cathy humiliated her by telling everyone her private feelings. In the 1939 film, she's not wrong when she calls Cathy out for her possessive jealousy. In fact, you could argue that Isabella is stronger than Cathy; once Heathcliff reveals all his bad traits, she falls out of love with him, does her best to resist him and eventually escapes from Wuthering Heights. Cathy by contrast knows what a sociopath he is, and continues to love him.
Darkness-Induced Audience Apathy: The two lead characters are sociopaths in a destructive relationship, and the sympathetic supporting characters get abused by them, die sadly or become cold and heartless because of their treatment. While the ending is happier than you'd expect, sometimes the story can feel so grim and pessimistic that it's hard to care what happens.
Many female readers insist that Heathcliff is a dashing hero, despite his many, many shortcomings (even to the point where they thought his digging up Catherine's body was romantic). The story itself makes fun of this sentiment among her readers by making 18-year-old Isabella Linton idolize him. Catherine admonishes Isabella that "He's not a rough diamond—a pearl-containing oyster of a rustic: he's a fierce, pitiless, wolfish man" and Heathcliff comments on Isabella's naivety and romanticism regarding him, mocking it later in the book.
Catherine the elder is likewise often imagined as an ideal romantic heroine, a survivor of abuse and the more sympathetic of the pair. In reality she's a sociopathic, tempestuous brat who at one point wants to marry Edgar solely for his money to secure her own comfort - while still keeping Heathcliff around for pleasure. Additionally while she's married, she still acts like a possessive Green-Eyed Monster towards Heathcliff (her warning Isabella off him is motivated by jealousy as much as anything else). Several adaptations (particularly the 2009 miniseries) file off some of her worse traits to make her slightly more sympathetic.
Fanon: Nelly is often imagined as an older woman, and portrayed as being middle-aged in Catherine and Heathcliff's youth. Actually in the text, she's only six years older than Catherine and the same age as Hindley.
Harsher in Hindsight: Heathcliff is Ambiguously Brown and trying to fit into a society of middle class white people. The 1939 film adaptation casts Merle Oberon as Cathy — she herself an actress of Mixed Ancestrynote She was born in India but her exact racial background isn't known, as she claimed to be born in Tasmania. who tried to pass for white.
In complete fairness, given Isabella Linton-Heathcliff's fate, it is difficult to imagine why anyone would constantly compare a book to Wuthering Heights and name the heroine of said book Isabella. It is very amusing that Twilight tries so hard to compare itself to this story, when it is in fact denouncing the kind of relationship Stephenie Meyer tries to glorify.
As Heathcliff begins his descent into suicidal madness, Nelly ponders the mysteries of his origins and wonders if he truly might be part goblin, demon, or vampire... But quickly dismisses such theories as "absurd nonsense."
In the novel, Nelly says "But where did he come from, the little dark thing, harboured by a good man to his bane?" Tom Hardy, who played Heathcliff in the 2009 version, would later play Bane in The Dark Knight Rises.
The two actors who played the toxic couple in the 2009 miniseries - Tom Hardy and Charlotte Riley - ended up Happily Married.
Heathcliff is the most famous example. He's a sociopath who ruins a bunch of lives out of a desire for petty revenge - and an abuser who is implied to have raped his wife. But his upbringing was far from ideal - where he was bullied by Hindley and constantly reminded of his place. Catherine was the one bright spot in his life, and even his relationship with her was unbelievably toxic. He's as much a victim of her as anyone else. Then after her death, he becomes more monstrous and ruins more lives than ever, but all the while is tortured by grief for his Lost Lenore.
Catherine I is an arrogant, vicious-tempered gold digger whose relationship with Heathcliff is toxic, but she's also an orphan trapped in an oppressive household with a drunken brother, as well as in a society that can't accept her natural wildness. By choosing to marry Edgar, she thinks she's doing what's best for Heathcliff as well as herself, hoping to free him from Hindley's abuse by supporting him with the Lintons' money, but instead is abandoned by him, and the turmoil both of her love triangle and of her dual longings for freedom and security drive her to madness and death.
Catherine II is introduced as cold and rude to everyone - but that's because she's been trapped in Wuthering Heights, had her inheritance stolen by her father in law and had to watch her beloved father die of an illness partly brought on by her actions.
Linton too purely on account of being Heathcliff's son, and losing his mother at the age of thirteen.
Misaimed Fandom: The famous quote "I am Heathcliff!" is actually very misleading if you just read the back cover. What this situation needs more proper context on is the differences between Cathy and Isabella. Cathy by many means is just as sociopathic as Heathcliff is, the love between them is pure to them but alien to many others who can't wrap their heads around it. Isabella on the other hand practically finds Heathcliff Troubled, but Cute to her own detriment as Cathy readily points out. One meets Heathcliff on his level while the other is full of naivety without fully thinking. There are very major differences if someone is applying to this trope to Heathcliff thinking like Isabella vs thinking like Cathy. Just to add further context, Nelly lets Cathy have it after her "I am Heathcliff" line with "If I can make any sense of your nonsense, Miss, it only goes to show me that you are ignorant of the duties you undertake in marrying; or else that you are a wicked, unprincipled girl." Nelly is not only confounding Cathy on her plan but the whole principle in general. As while some people are the Cathy or the Isabella, some others might be the Nelly and find this whole conversation ridiculous.
Narm: In the 1939 film right before she dies, Cathy's eyes widen in such a way that makes it look like an Eye Take.
Some Anvils Need to Be Dropped: Emily Bronte hammered in the anvil about gender and class inequality in Georgian/Victorian society - with Catherine being torn between a happy life with the man she loves (yet is lower class) and a life of comfort she's expected to sacrifice her own happiness for. It's notable for Cathy being forced to conform to society's expectations of what a Georgian/Victorian Proper Lady should be. The first wedge between her and Heathcliff properly comes when she's spent weeks at the Linton house, being taught how she's 'supposed' to act. This forced conformity is what drives her and Heathcliff apart. Likewise it's all too easy for Isabella to be Defiled Forever thanks to Heathcliff using her for his revenge, and Catherine II is later screwed out of her inheritance thanks to the sexist laws of the time.
The many lines calling Heathcliff "dark" conjure up thoughts of black Africans in modern readers' minds. Regency Era readers however would instead think of olive complexions (Heathcliff is often suspected to be Romani).
Catherine the younger falls in love with both her cousins. Marriage between first cousins wasn't uncommon among the upper classes and didn't fall out of favor until after World War I.
Isabella is subjected to an absurd amount of victim blaming for being seduced by a predatory man, trapped in an unhappy marriage with him and is considered Defiled Forever when she escapes with her child by rape.
The main obstacle in Cathy and Heathcliff being together is their class difference. Cathy would be expected to marry within her class, which is why she doesn't just elope with Heathcliff. This just makes her even less sympathetic to modern readers. Of course a big part of this is intentional to show how horrible class divides are in keeping lovers apart. The book does end after all with Catherine II falling in love with the poor orphan Hareton (who however is relatively equal to her class because his father was a land-owner).
Values Resonance: A foolish and sheltered young woman shallowly falls in love with a bad man, marries him, and suffers horribly? Ask any domestic abuse counselor in the world if this part is outdated. They'll laugh at you.note Heathcliff reminds Isabella that he's within his legal rights. Today he wouldn't be.
Vindicated by History: When it was first published, the novel had a divisive reception from critics who felt it was well written but far too dark and the characters too unsympathetic (plus some shock that a woman could write such a grim story). These days it's held up as a classic and iconic work of English literature.
The Woobie: The universe seems to conspire to make Isabella Linton's life a nightmare. She develops a Precocious Crush on Heathcliff that a jealous Cathy reveals to others - which humiliates her and makes her withdraw from everyone. This leaves her prime fodder for Heathcliff to seduce her as part of his revenge - and as soon as they're married, she's tortured over the years until she can take no more and flees for her life.