There's something rather sweet about how despite wanting to wither the whole forest, Even Evil Has Loved Ones, and the villain and his son actually have a good relationship before The son's death.
Ronin allowing Grub to become a Leaf Man.
Going against the Leafmen's, and the order of nature's, code for never revealing themselves to humans, the end shows that MK, even after transforming back to her normal size, keeps in touch with Nod and her miniature friends through her father's cameras akin to Skype.
In the Creative Closing Credits, at the 'production babies' section, there's a picture that MK drew of her complete family (her, her father, her mother, Ozzie) when she was a little girl. Also counts as a Tear Jerker.
Early in the movie, MK states she's going through the Five Stages of Grief over her mother and she intends to do it alone, to the disappointment of her also mourning father. However at the end of the movie when MK grows big again, it's hinted that she's willing to let them get through the grief together.