Getting the Chance Time Bonus for "Continuing Dream" in F wherein Miku, Luka, Rin and Len join hands and reach out to the player at the end of the song.
The chibi Vocaloids' hard work and the revival of the world in "God-Tier Tune."
The birthday events in F, especially the one for the player.
Several of the Item Events where the recipient is super gleeful and appreciative of the gift they received, doubly so if it's flowers or a stuffed animal.
Even more so when the character uses the gift to cook something for, give something back to or share with the player in return. Good examples are the bale of rice, cooking pot and cream soda events.
The words for Tell Your World, where Miku is actually singing of the very fact she wants to bring together the entire world with her songs. It's impossible, when you actually understand the words, for you not to want to say "Yes, Miku, We're listening, keep going, you're doing great."
Despite the fact the song is a controller destroying monstrosity, The Intense Voice Of Hatsune Miku does get a bit of heartwarming in, as Miku's song is about averting the bad end of her death, instead deciding that she will put her fate into the hands of her fans, and not declare herself a goddess above them all, instead being the professional idol she was made to be until she cannot sing any more, and the song ends with Miku looking forward to the future, one where she will sing for many years to come.
The "Affection up!" scenes in F 2nd with all six of the characters.
Going back to 2nd we have the ending to "Gigantic Girl," where Miku and Godzilla are arm-in-arm and waving to the viewer, plus the story of "Gemini" where Rin and Len make up after a huge falling out.
The image of Miku getting up on stage and singing in "Though My Song Has No Form," in order to reach out to anyone who will hear and let it touch them. In a sense, it feels far more personal to not get the Chance Time bonus in the F 2nd version as she appears to be singing directly to the player.
The ending of "Amatsu Kitsune" in Mirai DX after fox Rin is finally able to fly.