Lamar's Pet the Dog with Rayna when she's smeared by the tabloids, telling her she should be nothing but proud of who she is, and screw anyone who thinks differently.
Avery sending an egg whisk to Scarlett before her professional debut, referencing his first encouragement that she could make it as a singer.
Glenn coming back to Juliette after her mother's death, despite how badly the two part terms.
After the tabloids discover Maddie is Deacon's daughter, it's all over TV. Glenn comments that it's good they've moved on from Juliette (her career was in freefall at the time), but Juliette replies 'She's just a kid. I'd rather they talked about me.'
Can we just add anytime Rayna's Mama Wolf tendencies come out? Despite all her romantic mess-ups, the way she, a big star, behaves towards her kids is really endearing and sweet.
When Scarlett's mother unexpectedly drops by for a visit, Scarlett is freaked. Avery turns up to her room next since they need to produce together, and she all but drags him inside. It's pretty obvious no-one else but him knows how Beverley has abused her, and how Scarlett needs someone with her to deal with her mom. Avery doesn't say a word, but it's obvious in his expressions he understands.
After the car accident seems like it's destroyed Rayna's singing ability, she's roped into a concert performance where the whole crowd starts singing for her, leading her to regain her voice.
A disguised Juliette (on tambourine) duetting with a busking Avery to an appreciative crowd of passersby, providing her with some much-needed positive vibrations after the rough times she's had lately.
Teddy telling Maddy she's wrong about him hating music, and he doesn't even hate Deacon. Deacon is the reason he has her, after all.
Juliette and Avery getting married. If there's one character on the show who deserves some happiness, it's Miss Barnes.
Jeff after Layla's suicide attempt, goes to get her and Will's show cancelled, which is later followed by a scene of Will saying that they can finally get divorced.
Overlaps with a tearjerker, but the way everyone behaves after Scarlett's breakdown. Even amidst the blame game being played it's blindingly obvious just how much a large amount of the cast care for Scarlett, and their reactions to it take up much of episode 20 for the second season. Bonus points for Deacon's speech to Scarlett's mother, that this really isn't about the differences between the two of them, but rather giving the best chance to 'that sweet girl' Scarlett. Also, Avery looking after Scarlett and the two reaffirming their connection, even though it's obvious neither one wants to get back together. They just have a history and know each other very well, in a similar but very different echo of Deacon and Rayna.
Just generally the way Avery behaves with and takes care of Scarlett right after her breakdown, from getting her offstage, to not letting go of her hand and staying with her.
Luke of all people has one when he tells Colt that he was glad to spend some time with his son, even if it meant seeing Rayna and Deacon together.
Juliette and Avery singing to their newborn daughter. Even if the episode smashcuts directly to the end credits just before Juliette suggests they call her-
Will coming out
Scarlett cutting her tresses off for charity. Especially since Clare Bowen did it for a very similar reason in real life.
The final episode on ABC provides genuinely happy endings for several characters:
Deacon brings Maddie home and reunites their family.
After Scarlett declared her love for him earlier in the episode, resulting in the possible breakup of their partnership, Gunnar kisses Scarlett onstage at the end of their performance.
Will gets an epic Moment of Awesome when he takes on a bigoted talk show host with Luke and Kevin assisting him, and ends the series reuniting with Kevin in a Big Damn Kiss.
The final scene of the series as a tribute concert brings out the entire cast of the show (including several actors whose characters were long written off) together for a bit song. The line "Celebrating Six Wonderful Years" is shown as the show's producers thank the city and the fans for their great run.