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.
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.
Moe: Maybelle. Just ... Maybelle. This is even 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.
It ups the Nightmare Fuel when we find out that the Dark Master symbolizes Jess' father played by Robert Patrick, while the father himself isn't that bad of a guy, it does stir up some repressed T-1000 memories.
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.
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 Narniarip-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.
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?