The Mosquito & The Bumble Bee

In The Mosquito and the Bumble Bee, the title characters start off as rivals -- each insect revels in ruining picnics and camping trips, but when they meet, they immediately see each other as rivals. Ultimately, though, they come to a realization that theirs is a rivalry based on trivial differences, and with a bit of soul-searching (not to mention some Googling), they eventually figure out that what they have in common is far greater than any trivial differences that might arise between them.