The last 15 minutes or so are heartwarming. Not gonna lie, I teared up a bit.
The elves, who all previously saw Arthur as nothing more than a clumsy, naive oaf that "would be more fitting in the South Pole" (an opinion that Arthur is secretly aware of), chanting his name while watching him ride Gwen's bicycle to her home to deliver it, with seconds to spare! And their voices fill the huge control room! *sniff*
Malcolm and company arrive to cover the sunlight for Arthur to deliver the gift before Gwen wakes up.
Arthur, Malcolm, and Steve seeing Gwen finding her gift and realizing Arthur should succeed his father.
Lets not forget this moment; after Arthur delivers Gwen's present, he falls in the snow on his way up to the S1 and gets snow on his face, and the wind puffs up his jacket. Gwen comes outside and catches a glimpse of him for a second before the S1 takes off. The fact that Arthur had become the new Santa makes it even more heartwarming.
When one elf scanned a child in the beginning, and got "56% Naughty," meaning no gifts in the stocking. An absolutely heartbroken look appeared on the elf's face, and he then promptly scanned himself, getting a "82% Nice" reading and thus letting him put presents in the naughty kid's stocking anyway.
Evie taking off for the first time in the film. The beautiful animation of flying over the North Pole and Grandsanta's speech about the tradition of taking the next Santa along for a ride brought a few tears to this troper's eyes.
The fact that the entire team of elves are IMMEDIATELY ready to help Arthur deliver that one single present may have made this troper's heart grow a size or two.
Any time Arthur is seen answering letters, or we hear them in his voice. It's not very often, but he makes sure to give some kind of answer to every single thing the children say, and comment on every drawing or picture he recieves. Truly, he is the man who cares about every child. Another little tidbit is that the elves go out of their way to make it look like the reindeer eats the carrots that children leave out, just to keep the entire magical idea alive. It's really quite amazing.
Have you noticed anything strange on the picture of the S1 during the epilogue? Now she's called EVIE.
Doubles as a Tearjerker, but the fact that there's a children's ward of a hospital shown. While they use it as a funny moment with the babies, it does bring to mind that some kids are in the hospital during Christmas.
Individually, these things are mentioned already, but it's worth saying just how devoted the elves are to their jobs. They are precise and uber-efficient, yes, but they also care about the kids SO much, and you can see that. They turn on the Christmas dinner, give the dog a bone, but the kids are where the elves really shine to me. They really can't stand the idea of a kid not being happy. There's the elf that scans themself over the naughty kid, the waker scaring them half to death, Bryony's determination for Gwen to have a nicely wrapped present. And there's the idea that one kid not mattering makes them basically have a breakdown and question everything they knew, and that, as mentioned already, they were IMMEDIATELY ready to help Arthur, because that one child did indeed matter, especially to those elves.
Arthur's faith in Steve - that if Steve helps them, they can deliver Gwen's present, and, subsequently, "I'll be the candle."