- The beginning shows us Arnold is just tired and not as enthusiastic as he once was. Arnold has been searching for his parents for about a year or two since "The Journal", but for him, it feels like it's been decades. For all his efforts, he is still no closer to finding his parents.
- On both a meta-level and In-Universe level, the fact that both Arnold and the audience have been denied a conclusion for years. Although while Arnold's been waiting at least a year and the audience has only waited 13, it makes no difference. The fans can easily empathize with Arnold's torment just the same.
- Everyone is celebrating that Arnold's class won the trip to San Lorenzo ... except Grandpa Phil and Grandma Gertie. It's painfully obvious they're afraid that they'll lose Arnold, just like they lost Miles. Or, they know Arnold wants to go hoping he'll find his parents and are afraid he'll only be bitterly disappointed.
Phil: This is just a school trip, not about you finding your parents.
- The trailer shows Phil trying to keep Arnold from getting his hopes up.
- Its not stated outright, but it is heavily implied that with Big Bob's Beeper business going bust, Helga's family had to sell their home and move into what remains of the old store.
- When the group is forced to hike through the jungle after their boat gets wrecked, poor Sid's Beatle boots get stuck in the mud and rip in half, turning him into a crying mess.
- The other kids turning against Arnold after their boat gets wrecked and the Eduardo accompanying them is revealed to be actually Lasombra, who convinces them that Arnold betrayed them. Including Gerald.
- Arnold's Despair Event Horizon after being captured by Lasombra. Which gets noticed by Helga, who starts to feel remorse.
- The Reveal that the Eduardo the group meets is really Lasombra in disguise and that he and his men faked the whole contest as a way to trick Arnold into coming to San Lorenzo as part of a plan to steal treasure from the Green Eyed people.
- When Big Bob and Miriam realize the kids are in danger their immediate concern is that Olga is with them, no word of Helga. Just, damn...
- Well granted, they do remember her after a minute. Bob himself at least actually remembered her name was Helga. Miriam just referred to Helga as "the other one". Still pretty awful though.
- As some might have guessed, Miles and Stella were indeed victims of the very disease they had come to cure. Even though they were ultimately able to synthesize a cure, and enough for all the Green-Eyed people, without the Corazon, they had no way of activating the mechanism that could aromatically spread it to the populace. What's more, it's revealed that the sleeping sickness only affects adults, and by the time Arnold has finally found the city, only the children are left to care for their comatose parents. These children have gone at least nearly a decade without adult supervision, and most importantly, experiencing their parents' love...
- Then when Eduardo reveals that the Corazon was lost in the fight with Lasombra to the Green Eyed children, they all start crying. Arnold joins them, with Helga beginning to tear up as well as Gerald desperately saying there has to be another way.
- A happy Tear Jerker, but Arnold finally reuniting with his parents once they are cured of the sleeping sickness and wake up from their coma.
- The last scene can be seen as this even though it's played for laughs. Even though Arnold has found Miles and Stella and they've come back to Hillwood to live with the rest of the family, they've still missed nearly the entirety of his life. Miles and Stella walk Arnold to school and say they'll wait outside until he's done when he tells them they can't go in with him. They do not want to be away from him.
- When Arnold initially thinks that finding his long-lost parents, saving the Green-Eyed People, and finally kissing Helga was All Just a Dream (again), his eyes well up with tears and he looks absolutely heartbroken. Though it is subverted only a moment later, those few seconds are an absolute Tear Jerker. What's worse is that, according to his mom this has happened several times since they got back. Arnold has been without his parents for so long that even after finding them and having them back home with him still feels like a total illusion for him. It's clear Arnold will need a lot of therapy.
- This bit from the credits can invoke happy tears (and on top of that it was placed before a In Memoriam of cast/crew who didn't live to see this movie getting the greenlight):Thank you to all the fans who wrote letters and signed petitions encouraging the making of this movie.
Tear Jerker / Hey Arnold! The Jungle Movie