Yukina getting Shigure — the most popular boy in school — to be her "fake lover." She sure has to have guts to be willing to go that far for the sake of her novel.
Yukina standing up against the Malicious Slander and a gang of Shigure's fangirls by exploiting all their embarrassing secrets.
Akira defends Yukina when Shigure's fangirls gang up on her about her closeness to Shigure. For someone introduced as a simple support character that is always found eating, one wouldn't expect that out of Akira. Doubles as Heartwarming.
Shigure turning the tables on Yukina when he tells her he'll make her fall in love with him, mirroring Yukina's words to him from the first chapter. Also doubles as Heartwarming.