Any of Jungo's Fate events that involve him and his adopted cat, Jungo.
The climax of Io's Fate events has her talking a young child out of killing himself, with Io admitting that she contemplated suicide, too, when her parents died and understands how the child feels. But she learned that, as long as there were people who cared about her, she could keep going and life wasn't pointless and that the child must have people that care about him, too.
Yamato's Fate events has two instances that really show how he has changed.
During his level 3 event, he is introduced to takoyaki by the protagonist, who previously promised to teach him about mundane things that made life great. Yamato tries it and winds up enjoying the food.
His level 5 event has him encounter a dying man, who offers a piece of candy to Yamato. He was going to give it to his daughter, but can't do it anymore and wants Yamato to have it, even telling him that he knows he's part of JP's, but bears no hard feelings. After the man dies, Yamato contemplates if he's even deserving of such a gift. He knows that he is utterly cold and distant to people and shows a bit of regret over not being able to return empathy.
Even sweeter, if the player goes for Yamato's route, Yamato sends an e-mail at the end of the penultimate day. He reiterates his previous lines of wanting to make a meritocracy and all, but the attached picture is great. An almost-finished plate of takoyaki, his new favorite food that the protagonist introduced him to.
Yamato: But for now, let's think about tomorrow, when you and I will change the world together.
The two Ticos are always happy when the player manages to save one of their party members from foretold death. When one remembers that they are digital extensions of Al Saiduq's will, it's obvious how he feels about this, too.
One of Makoto's Fate events has her and the protagonist come across a group of rioters that are being cornered by demons. The rioters are scared for their lives, but are intent on fighting their way through. Why? They want to keep a young child from their group safe.
After defeating Yamato on the Anguished One's route, Yamato reveals that the Anguished One is the last Septentrione. Regardless, the protagonist just smiles and doesn't care, considering the Anguished One his friend. Even the Anguished One is touched by those words.
Otome's Fate events revolve around her trying to balance her job as a doctor and being a mother to her adoptive daughter. Their relationship is strained because Otome is often working long hours and leaves Koharu alone, which makes her think she's unfit to be a parent. In the final event, Koharu is wandering around the demon-infested and slowly disappearing world and Otome can't contact her. If the protagonist manages to find Koharu, she thinks Otome is better off without her, since she isn't her 'real daughter'. When Otome joins in, she practically glomps the girl and is just thankful that Koharu is safe and how much she loves her. Koharu hugs her back and the protagonist leaves them for a moment of privacy.
The Restorer ending, if the player has managed to keep everyone alive and recruited back. Everyone is alive and well, with Joe walking with his longtime girlfriend; Airi and Hinako performing on the piano and dance, respectively, together. And the protagonist and Daichi meet Io at the subway station again, with her being more open about wanting to hang out with them.
The Egalitarian and Liberator ending show humanity really working together, helping each other out and not being bothered by status or money. Just working on making each other happy. Even if the Liberator ending is a rather dark example under its happy atmosphere.
Overall, seeing all the party members and how they have changed in the regressed world, compared to how they were during the Septentrione arc. Keita is more open about treasuring his comrades and Airi and Hinako still butt heads, but are working well together as an idol duo. Even Yamato wants to protect everyone now, not just those he deems strong enough to be worthy.
In the beginning, everyone gaining their memories of the previous world. The memories are images of things that have occured, even off-screen, and some are of the funnier moments. But there's also Hinako teaching Airi and Io how to dance and Otome helping Koharu make a drawing of the protagonist.
Yamato willingly staying in the Astrolabe to continuously fight Canopus' minions, just so he can keep the protagonist's data in the Akashic Records safe. He barely gets a break in-between them; a dialogue choice even implies that he's so exhausted that he's falling asleep between sentences.
The Arcturus battle. The protagonist uses the power of Shiki-Ouji to dispel the status ailment caused by Arcturus' Quasar ability, which makes everyone on the field weak to the four elements. Using Shiki-Ouji's ability, the party members become safe, but the protagonist will take on all the damage caused by Arcturus' ability. What really makes this heartwarming is that the entire party insists that the protagonist not do that, unless it was absolutely necessary during the battle. They practically beg him to not go through with it, ready to take on the Plough of Death, if it meant the protagonist was safe. If the player does use Shiki-Ouji's power, the team immediately tell each other to hurry up and defeat Arcturus because they don't want the protagonist to have to suffer as much. Never has the power of friendship felt so good!