In "Cat Burglar", the Miao siblings successfully capture the titular burglar together. What makes this especially awesome is when one learns that in old times, Siamese cats were bred to guard temples and keep its valuables safe. In other words, Sagwa and her siblings may be "sneaky as a cat", but they ultimately used their ancestral gift to save the royal family's valuables!
Fridge-Heartwarming: In "A Catfish Tale", Sagwa's grandfather insisting the catfishes are their family takes on a whole level of sweet if one is to believe Uncle Catfish's story is true. Remember how in the story, Shen-Shen's grandfather and ancestors promised that she'd never stop being a part of their family? By saying the catfish are their family too, Sagwa's grandfather and Uncle Catfish are making certain that they keep the promise made to Shen-Shen: even generations later, she and her descendants are still a part of the Miao family.
The titular "Master of Nothing" teaching the Magistrate's daughters their respective talents by pretending to be bad at them isn't just about tricking them into learning from their mistakes. If you notice, he doesn't make too big a deal that he's bad at them. It's meant to teach that mistakes aren't the end of the world, and the learning process can be even more fun than simply being good at your talent.
In "The New Year's Clean Up", the Rat nibbles all the dumplings meant for the feast. While selfish on his part, rats like to nibble their food to make sure it's not poisoned. So it wasn't just selfishness when he told Sagwa he was trying to find the "right" dumpling.
