Season 1, Episode 5: Rikka's first genuine smile in the series, after Yuuta gives her the new email address he created for her ("black-raison-d'etre") in this chuunibyou persona.
Season 1, Episode 7: Yuuta's concern for Rikka when she behaves strangely during the summer trip. After Yuuta learns what happened, he consoles her when she's depressed and cheers her up. During the scene on the roof, Yuuta catches Rikka in his arms when she jumps down (although they both hit a bush). He goes along with Rikka's delusions and bikes both of them to Rikka's old house because he thought it would make her happy.
In spite of their rivalry, Shinka was still seen taking care of Sanae twice in episode 7.
Season 1, Episode 8: Yuuta and Rikka's interaction of whole episode.
Season 1, Episode 9: Everything about Rikka's Love Epiphany and her fall from the roof, leading to Yuuta's embrace and his own Love Epiphany.
Season 1, Episode 10: Rikka and Yuuta's love confessions to each other, and the lead up to it. Yuuta getting into chuuni character to ask Rikka to be his girlfriend. Their pinky holding. Rikka singing her father's favorite song at the festival.
Rikka and Yuuta also have a nice dinner under the bridge, including a Call-Back to episode 10 with the lights in the distance as well as episode 8 with Rikka opening the onigiri wrapper. Rikka even smiles when doing this, which is especially sweet considering she's been doing nothing but suppressing her own happiness throughout the episode.
Season 1, Episode 12 (Season Finale): when Yuuta invoked Rikka's Chuunibyou imagination the way it was meant to have been invoked to help her say goodbye to her father and move on rather than escape the reality of his loss. Boy, did it paid off.
Season 1, Episode 13 (OVA) Shinka and Yuuta taking care of drunk Rikka and Sanae. Yuuta carrying drunk Rikka on his back home. Yuuta admitting he bought tickets for Rikka and him to attend a beautiful sightseeing boat. The cute Accidental Kiss between Shinka and Sanae at the end of the episode.
Season 2, Episode 1: Everything about Yuuta and Rikka living together.
The fact that Rikka has the same friends she made in episode 11. It does a nice job highlighting that even though she's back to being a chuunibyou, she can still move on to having a larger social group than just her peers in the club.
Season 2, Episode 2: Yuuta remembering one of Rikka's desires and takes her to the aquarium to her great delight and happiness.
And their little discussion at the end about how to proceed with their relationship.
Season 2, Episode 3: Yuuta touching noses with Rikka to seal another promise for their relationship at the end of the episode.
Season 2, Episode 4: Sanae finally accepts that Nibutani is the true Mori Summer and immediately tries to mend her ways in the sweetest way possible. She overdoes it though, embarrassing Shinka in front of the whole school as she was on the cusp of winning Class President. Their relationship goes back to normal.
Prior to the resetting of their relationship, Nibutani does something truly sweet for Dekomori as they get closer. She dons her old chunibyo ensemble and briefly becomes Mori Summer again for Sanae, who's moved to tears from the display.
Season 2, Episode 6: Rikka comes to see Yuuta after-hours and ends up being forced to sneak into his bed. After escaping, she gives him a cheek kiss, which Shinka witnesses.
Season 2, Episode 7: The last three minutes of the episode. After the misunderstanding regarding Satone is cleared up, Yuuta gives Rikka her birthday gift: a brand new parasol alongside a magatama. The episode ends with Rikka (with the most adorable smile on her face) telling Yuuta she loves him. So much d'awwww.
Season 2, Episode 8: Sanae defends Shinka from her imposter's attack regardless of her feelings that Shinka is a fake as well, saying that at least Snika isn't a bad fake.
Before that, Shinka rescuing Sanae from said imposter's attempt at sexual assault, as well as her speech about Sanae that shows just how much she knows her and cares about her.
Season 2, Episode 9: Rikka calling upon her bond with Yuuta during a practice chuuni battle with Satone to revitalize herself.
Season 2, Episode 12 (Season Finale): Yuuta's monologue to Rikka about how he loves her endlessly and doesn't care what physical expression they do as long as they are who they are and love each other. The near-kiss at the end of the episode is very cute. Chimera having kittens is also very cute and symbolic of their relationship.
Season 2, Episode 13 (OVA): Yuuta waiting up late at night, setting out some food and writing a note to Rikka after their fight put them at odds and Rikka was away hiding with Satone.
