Adaptation Displacement: Though the book is a popular children's book, the 2007 film is often more well-known. Most fanworks are based on it and lot of fans complain that Leslie is too tomboyish in the 80s film, despite that being book accurate.
Alternate Character Interpretation: Jess's father's annoyance at him could just be a "Well Done, Son!" Guy thing. Or alternately he clearly cherishes little May Belle - and shows her the most affection throughout the film. Perhaps he's annoyed at Jess excluding his little sister so much?
Ear Worm: From the film, AnnaSophia Robb's "Keep Your Mind Wide Open", a sweet little song that reads as an anthem for Cloudcuckoolanders everywhere.
Epileptic Trees: It's not uncommon to find an LDD fan believing that Terabithia was real all along and that Leslie was really abducted by the Dark Master.
First, there is the scene when Leslie, Maybelle and Jess return from Easter mess, They discuss faith and Maybelle says to Leslie: "If you don't believe in Jesus, you go to Hell when you die". Leslie dies less than a week later.
In the film, Jess coming home and saying "Hi guys" as his Catch Phrase with no one responding rings more harshly when he says it and his mother frantically grabs him and his parents have to tell him Leslie is dead.
One of the writers of the 2007 film is the author of the book's son. So that movie is practically a grown-up Jesse remembering his own youth and his best friend back then.
He's Just Hiding: Most fanfics for Bridge to Terabithia fall into two categories: "What If Leslie didn't die?", and "Leslie didn't die, period". This is actually done In-Universe as well, with Jesse believing that her death is all lies, believing he saw her over at her house when they went to pay their respects, and finally mistaking May-Belle's voice for Leslie's.
Leslie's imagination in creating the fantasy world is a little amusing if one watches AnnaSophia Robb in Race to Witch Mountain where she's again imaginative - and actually does have magic powers. What's more is that her brother in that film is played by Alexander Ludwig, who plays Josh Hutcherson's Arch-Enemy in The Hunger Games.
May Belle being crowned the Princess of Terabithia if you've seen Bailee Madison in Once Upon a Time where she plays a fairy tale princess for real: the young Snow White of all people.
It Was His Sled: Leslie dies. Spoilered because it's not as well known as, say Darth VaderbeingLuke's father, but since it is one of the most discussed things about the story, it's hard to avoid hearing about it whenever the book or movie is brought up.
Jerkass Woobie: Janice turns out to be one. At the end of the film, it's implied she and Jesse may become friends.
Memetic Molester: Miss Edmunds. Modern audiences view her less innocently than audiences in the 70s did. Her closeness to Jess in itself isn't unusual, but her taking him on a trip alone is less justifiable.
Moe: Maybelle, at least in the second film. This is lampshaded by Josh Hutcherson and AnnaSophia Robb in their commentary, the former of whom calls her "just the cutest kid ever".
Moral Event Horizon: Scott and Gary cross it when they up their bullying of Jess following Leslie's death, Scott going so far as to outright taunt Jess over it in in class, complete with a smug smile on his face the whole time.
Tainted by the Preview: Those who read the book knew that the story isn't a fantasy adventure, but rather the bonding experiences of two kids in a realistic setting. Seeing the 2007 film adaptation's trailers, which centered around the fantasy world imagined by the kids but now fully populated by CGI creatures, caused them to believe that the filmmakers completely missed the point of the book and were instead trying to make a Chronicles of Narnia (the book series that Jess and Leslie compare Terebithia to in the book) rip-off that the marketing strategy seemed to promote. In some cases, this turned them off from seeing the film altogether, even though the film was actually truer to the book than the trailers would lead one to believe.
In the book, Jess's mother is worried about his best friend being female. Because it means he might be gay. The film on the other hand, Jess seems to get odd looks from his family when they meet Leslie; however, it seems to be that they're surprised he might have a girlfriend.
Also in the book, when Leslie tells Jess that Janice's father is abusive, Jess at first responds that most kids' fathers beat them; Leslie then has to clarify that this kind of beating is the kind that gets you sent to prison. The reason why Janice was crying was that she was telling her friends, obviously looking for sympathy, and they tell the school. Jesse thinks of how stupid that was because Kids Are Cruel. Understandably, in the movie this is changed to Leslie starting by saying that Janice's father hates her, hits her, and got the cops called on him, hence how everyone at school knows.
Jess's teacher calls him up to spend the day with her when her nephew cancels. Probably fine in the 70s but would raise a couple of eyebrows with the alarm over the Pedo Hunt today. Especially since the implication is that the teacher calls Jess personally rather than asking his parents for permission.
What an Idiot: Maybelle, you're a sweetie and all, but if you find a ring of keys lying on the floor of the greenhouse, don't you think you oughtta tell your parents?
Jesse starts out as one already, though with Age-Appropriate Angst about having four sisters and having to wear hand-me-downs. The angst quickly gets less age-appropriate.
Leslie's parents after their daughter dies in a freak accident, right in their backyard. They act gracious at the memorial service, thank Jesse for being such a good friend to her, and apologize for wanting to keep Prince Terrien as a memento. Within a few weeks they move, just after they had finished painting the living room.
Maybelle is another one, given she worships her brother but he sees her as an Annoying Younger Sibling. Fortunately by the end they patch up.