The note left with the sugar cube. "You forgot something."
Shawn and Arrietty exchanging farewell gifts, showing exactly how much the two have grown closer in the short time they've known each other.
After the above, when Arrietty is shown being sad on the teapot, Spiller shows a surprisingly large (and adorable) amount of emotion as he excitedly hands her a berry that he kept stored in his cloak to cheer her up. It works and his expression of pure glee makes it all the more precious.
Aunt Sadako/Jessica indirectly learning about the Borrowers. Unlike Haru, she's perfectly content to just know they're real, and doesn't feel the need to prove it to the world.