In "The Twenty-Foot Root," the ending of "The Right Size," Johnny's song to Root to help him feel better about being little.
Johnny: You're the right size, naturally. You're who you're supposed to be and one day soon you're gonna realize. Your big smile and your big heart, they're most important part. And they will always be the right size, you'll see. You're the right size to be friends with me.
In season 2, Gwen and the sprites meet for the first time. Granted, it was out of necessity and there was a bit of a shock between both parties at first, but Gwen and the sprites genuinely got along by the episode's end.