The close-up on Nice's and Jacuzzi's intertwined hands as they make a dash in the opening.
Nice and Jacuzzi are basically the Crowning Pairing of Heartwarming, especially once you hear their backstory: Back when Nice was a kid, she got a little too reckless with explosives and ended up blowing out her eye and a good deal of skin on her face and arms. After spending the majority of her recovery as a depressed, reclusive wreck, she hears Jacuzzi rapping on her window and sporting a massive tattoo on his face. Turns out that as soon as he heard of the accident, he rushed straight out to get it so that Nice wouldn't have to feel disfigured and alone.Awwwwwww.
When Jacuzzi faces off against Graham his entire gang shows up (seemingly independently) to back him up. When Graham accuses Jacuzzi of ignoring his instructions to come alone the entire gang replies by saying that they all came alone or words to that effect.
"I wish I could kill you now and forever." The expressions on both their faces is strangely touching.
Something about Isaac and Miria's final scene will make you grin and tear up, even.
"Isaac and Miria Unintentionally Spread Happiness Around Them."- A Crowning Episode of Heartwarming.
Czes and Maiza's scene at the end of the anime.
Elmer and Czes have a scene in 2001 that counts as this. Czes is questioning the nature of humanity, as the trust and kindness that Maiza and the New York immortals have shown him contradicts the cynical view that Fermet's betrayal instilled in him. He questions whether Elmer's unconditional trust in him is genuine. Elmer's response is to grab Czes's right hand and put it on his own head, telling Czes to stop worrying about it and just be glad that people trust and care about him.
Chane and Claire's final scene on the anime, more on Chane's side as she lived her life so far as a pet, since Huey only thought of his own daughter as a walking keeper of secrets and a bodyguard, but Jacuzzi and Claire (mostly Claire) started to make Chane open up to new bonds of friendship and love, specially love by Claire's unique way of proposing; in the end we can actually see Chane smiling for what may be the first time ever for her. Love truly is a beautiful thing.
Czeslaw Meyer has come to believe, as a result of his Tragic Past, that he cannot trust anyone, not even his friends, and when he finds that Isaac and Miria are immortals he worries that they will devour him. Instead, they go to great lengths to rescue him, and when they believe that the monstrous "Rail Tracer" is trying to eat him, both of them throw their own bodies over him to protect him, moving him to tears with their wholehearted kindness and their later assertions that he's a good person. At the very end, when he arrives in New York, it is revealed that he had taken the journey their aboard the Flying Pussyfoot with the purpose of devouring Maiza. When he meets Maiza, he is afraid that he will be devoured, but instead Maiza pats him on the head with his left hand as he comforts him, causing Czes to break down in tears and embrace him.
The whole ending of Baccano! (episode 13, not the last 3 extra episodes) to This Troper was one huge Crowning Moment of Heartwarming. Everyone comes back to life after being shot, thanks to Isaac and Miria sharing the Elixir of Immortality with everyone, thinking that it was ordinary liquor. Firo manages to save Ennis from Szilard. Maiza (who at first had been sad that they've become immortal and now will not be able to die like him) smiles when he sees that everyone is going back to drinking and partying.
Ennis: Could you listen to this last request of mine?...Please don't forget me.
Claire's speech to Chane at the end of Episode 15 and her reaction is kind of adorable, albeit in the bizarre way which results from placing the words Claire and adorable in the same sentence.
"I love you so much from the bottom of my heart that it's troubling!...I'm sorry. I lied. It's not actually troubling."
When rescuing the wounded Czeslaw from under the train, Isaac and Miria end up losing their footing and going flying into the air with Czeslaw. Their first instinct is to wrap their bodies around him so as to minimize the damage the impact would cause to him. Awwwwwww.
When Firo asks Ennis to say her name to just for the sake of hearing it. I mean, aww!
Firo's response to Ennis telling him that Szilard created and can control her is to tell her that she's way too cute to be related to someone like that. D'awwww.
Isaac, Miria, Firo, Maiza, Ennis, and the rest of the Martillo family meet up again in 1932 to play around with dominoes. After all the trouble they went to, this troper believes that they need a nice break.
Firo's relationship with the Martillo family can be considered this - not only was did they adopt him from the streets, they also seem to consider him family just as much as he considers them. The fact of Firo's Undying Loyalty towards the Martillos just makes their older sibling-esque teasing even sweeter.
When Firo is sent to Alcatraz and meets Ladd there, they quickly become friends. When Firo mentions that last he heard, Graham had gotten into trouble with the Runorata Family, Ladd immediately says that the first thing he'd do once he got out of prison was go help Graham out.
Isaac : Iím sorry, Miria! My wallet was actually in my pocket. At the end of Alice in chains, Isaac apologizing to Miria about leaving her alone while he was in jail. This troper cried tears of joy.
Miria's Letter to Issac in the prelude of...one of The Slash books (can't remember exactly which one). Pretty dark actually, but also shows just how much they love each other.