Alternative 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?
Fanfic Fuel: Some fics that spare Leslie will kill off someone else to preserve the theme; Jack Aarons is probably the most common "victim."
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.
It Was His Sled: Leslie dies. Spoilered because it's not as well known as, say Darth Vader being Luke'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.
One True Pairing: There's one kind of Terabithia fan, and that's the kind that ships Jess/Leslie.
Paranoia Fuel: There's always a chance someone who is close to you could die in a freak accident.
Even more so when you consider the fate of Lisa Hill, on whom Leslie was based. While Leslie's death is subtly foreshadowed throughout the book, with the use of a rope swing that could be reasonably expected to weaken with time, the days of rain that flood the creek, and Jesse's own misgivings about going to Terabithia; Lisa's death was even more freakish. She was struck by lightning on a sunny day.
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, given she worships her brother but he sees her as an Annoying Younger Sibling. Fortunately by the end they patch up.
Alternative Character Interpretation: Are Jess and Leslie platonic best friends or is there a budding Puppy Love? On the one hand, the book clearly plays the No Hugging, No Kissing trope straight. On the other, Jess' internal narration twice refers to Leslie as beautiful, and he becomes inexplicably angry (inexplicable even to himself), when Brenda makes a disparaging comment about Leslie's femininity.
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.
In the book, Jess's mother is worried about his best friend being female. Because, according to the time's values, it means he might be gay. In order to preserve the awkwardness, the film changes it to him receiving odd looks from his family when they meet Leslie, as if they're surprised that Jess might have a girlfriend.
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 had told her friends looking for sympathy, and they instead told the school. Jesse just thinks that it's 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. In the 70s, it would have been a sign that she was conscientious and willing to go above and beyond for her students; nowadays, it would raise a couple of eyebrows with the alarm over the Pædo Hunt today. It turns even worse with the implication that the teacher called Jess personally rather than asking his parents for permission.
Leslie being a secular atheist is at odds with her religious small-town; Maybelle has no issue telling Leslie that she'll go to Hell for it. Being openly an atheist was much rarer in the 1970s, especially in rural America. Many viewers find the character's a bit too bigoted towards Leslie's lack of religious beliefs, despite the fact that such reactions weren't uncommon (and still aren't, to a degree, in rural areas)
Viewer Gender Confusion: Many fans of the 2007 movie get confused about Leslie in the 1980s adaptation. Some even think she's a boy. This is how Leslie looks in the book; in fact, she is even more androgynous in the book. The 2007 film gave her a huge Girliness Upgrade.
Adaptation Displacement: Though the book is a popular children's book and is often required reading, the 2007 film is often more well-known, and the 1985 TV film tends to be forgotten altogether. Most fanworks are based on the 2007 film and a lot of fan complain that Leslie is too tomboyish in the 80s film, despite that being book accurate.
Awesome Music: From the film, Anna Sophia Robb's "Keep Your Mind Wide Open", a sweet little song that reads as an anthem for Cloudcuckoolanders everywhere. Meanwhile there being fans that are only aware of the movie.
Catharsis Factor: Watching Jess sending Scott the bullying-jock flying into the wall with a Megaton Punch for making a disrespectful joke about Leslie's death was oh so satisfying. As was seeing Gary Fulcher's bloody nose, courtesy of Janice, after he pushed Jess in the hall.
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.
Fanfic Fuel: Along with the Epileptic Trees, common LDD fanfiction involve, Jess returning to Terabithia to rescue Leslie from the Dark Master.
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.
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.
Jerkass Woobie: Janice turns out to be one. At the end of the film, it's implied she and Jesse may become friends.
Like You Would Really Do It: When watching the scene where Leslie's death is revealed, viewers who had never read the book looked at who produced the movie and called BS, saying there was no way Disney would make a movie where they killed off a main child protagonist. They were wrong.
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 class, complete with a smug smile on his face the whole time. It made the Megaton Punch Jesse gave him very well deserved.
Narm: The book was written in the 1970's and as such the 2007 film has a lot of slang that's a little outdated. It's usually the taunts coming from the bullies.
Narm Charm: The "free the pee" scene is silly but also amusing too.
Spiritual Adaptation: The film can be viewed as a stealth remake of My Girl but with genders reversed. Of course, My Girl is arguably this for the for the book of Terabithia, which predates it by 14 years.
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 had 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. 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.
Values Resonance: The change of Leslie's character from a straight-out atheist in the book to an agnostic who definitely seems to be considering the existence of God in the film does reflect the changing times, as in the past, people would have thought someone could only be religious or atheistic, but in recent years, there has been more thought given to agnosticism, theism, spiritualism and the likes.
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?