Many critics have called this movie the best Superman film in history.
At the end, we find out that The Giant's self-repairing mechanism still works. A Sequel Hook that never came to be? (This movie has been Vindicated by History...)
At the end when we see that Hogarth has become friends with the kids who originally picked on him.
General Rogard sending the only piece of the Giant they were able to recover to Hogarth.
Hogarth sending it on its way once it activates.
Dean's involvement with Hogarth in general is pretty damn heartwarming. He starts out by being nice to him at the diner despite how it turns out for him, then he very kindly doesn't rat Hogarth out when he finds him at the scrap yard, he protects him when he sees the Giant for the first time, and then agrees to help the two of them. He automatically slips into a caretaker role without being asked and even gives him encouragement when Hogarth admits to be bullied. Dean goes above and beyond being a Parental Substitute and even ends up in the role permanently.
The scene where Dean and Annie first hit it off. Dean's stunned to meet someone who actually likes his work, and the way they meet and chat as the spark ignites just feels completely natural and sweet.