Noel's mere presence. If her childlike curiosity, determination to fulfil the wishes of the people who called her, and undying joy won't melt your heart, who knows what will?
Adding onto that, every interaction she has with Nonoka is adorable. The sweetness of their sister-like relationship carries a lot of this series.
Most of the flashbacks throughout the series showcasing how close of a group the main characters were before Nonoka had to leave. Especially the interactions between Nonoka and Shione, which adds further tragedy to how their relationship is like throughout most of the series.
Episode 1
The fact that Noel was patiently waiting for Nonoka to return for the entire 7 years she was gone, and is nothing but overjoyed when she gets to see her again.
Nonoka's emotional reconcilation with Noel after finding out she wasn't the one who cracked her mother's picture.
Episode 2
Noel standing on her tiptoes to hand Nonoka a leaf umbrella she got, followed up with Nonoka deciding to share the umbrella with her instead.
When Nonoka requests Noel's help with getting rid of the saucer alongside Yuzuki, Noel agrees to it, knowing full well that she's the saucer.
Episode 4
While this episode is mainly a tragic one, there are at least two sweet moments to note.
And Noel also going through with her promise to aid Yuzuki in her campaign to drive the saucer away.
Episode 5
When she realises that Nonoka chose the anniversary of the last fireworks festival to try and set up one while the saucer is still around, Yuzuki tearfully asks Noel if she's happy before rushing over to reconcile with Nonoka, which can also double as a Tear Jerker.
Episode 6
Feeling immense guilt over slapping Nonoka in episode 4 throughout a good chunk of this one, Yuzuki eventually asks Nonoka to slap her, convinced that's the only way she can be truly forgiven. Only for Nonoka to just give her a tap on the face, believing that Yuzuki doesn't deserve a full slap and being more than happy with just being friends with her again.
Up until this point, Shione has only been seen acting cold to the people around her, especially Nonoka. So it's refreshing to see her somewhat enjoying her time at the hot springs with Noel.
Episode 7
Shione requesting Noel to tell Nonoka that she wants to see the meteor shower with her, implying that there's still a small part of Shione that wants to reconnect with Nonoka.
Episode 8
And the above sentiment comes full circle during the incredibly sweet reconciliation scene between Nonoka and Shione, topped off with Shione recreating what she said when she first met Nonoka. If only it lasted.
Episode 11
Every character coming together at the observatory and enjoying time together like they used to all those years ago during their final moments with Noel, who's due to disappear now that everyone's wishes have been granted.
Episode 12
After spending an entire episode trying and failing to get her friends to remember Noel's existence after the Cosmic Reset where it seemed to be only her who could remember, Nonoka comes across Shione at the end of the episode, who reveals that she also remembers Noel.
Episode 13
Seeing Shione as way less cold, more encouraging and nicer towards Nonoka is sweet enough as is, but knowing that she also remembers what happened following the time reset makes it even sweeter.
