Early on, when Kouta realizes that Nyu endured the cold damp surf to try and get him a sea shell to replace the one she broke.
Later on after hearing Kouta talk about his last moments when his little sister Kanae and seeing his sad face. Nyu cuts her hair and impersonates Kanae saying she forgives him in order to console him.
Mayu has several as her backstory is revealed. One, when she reaches the beach and feels safe from her parents. Two, when she first meets Wanta. Three, when the bakery merchant gives Kouta and Yuka a birthday cake for her, and shortly after this, Wanta, having ditched his supposed true owner, comes scratching at the door of Maple House, having faithfully followed Mayu to their new home.
Nana, each time she tries a new food or realizes that she has a home at Maple House. Also when she sticks by Kurama during his bout with mental illness, when he tells her she was nothing but an experimental subject to him.
Kurama, when his love for his adoptive daughter Nana is so fierce, he kills Barbara, a vicious clone of his real daughter Mariko, to protect Nana.
But let us not sell the love he had for said real daughter short, as it's just as heartwarming and tearjerking. In the anime, they both die together, in each other's arms, with Kurama imagining a happy life together that could have been. In the manga, the same thing almost happens, but instead they both live through it and Mariko ends up with a different death.
Also, Mariko and Nana actually bond over their mutual love for their father right before Mariko's death in the manga, with Mariko telling Nana to take care of Kurama before she commits her Heroic Sacrifice to stop Lucy.
Nozomi, when she accepts the encouragement of Kouta and Yuka to keep on singing, and later, when she asserts herself to her worried and misguidedly overprotective father.
Yuka, when she flees to the beach, believing Kouta loves Nyu more, only to have Kouta come to retrieve her, angry that she should worry him, and proving he loves her by his concern.
Lucy, when she sings while healing the mortally wounded Kouta, knowing that doing so will cause her body to melt—and this is after he said he hated her for what she did to his family.
Kouta, in the very last panel of the manga, as he smiles and sees that his daughter's playmates are somehow connected with Lucy and Nyu, possibly their reincarnations.
Anime: Kouta is still unforgiving, but ends up openly admiting that he loves her, then a tearful Lucy kisses him before leaving.
Dear god, if you didn't cry at this part, then you have no soul.
Mayu finding out that Bando is still alive in the last chapter despite being cut in half by Lucy the last time she saw him. Considering this is a series where Anyone Can Die even the protagonist, it was a relief to see a previously thought dead character turn out alive and well.
Simalarly, the survival of Anna Kakuzawa and the Agent.
The ending to the chapter that explains Nozomi's backstory We see the cassette tape that her father broke earlier taped back together in a drawer