The Cat in the Hat Knows a Lot About That! 1x37

It's Valentine's Day and Nick and Sally disagree hotly on how to decorate the card they're making for the Cat. This means they aren't really best friends—The Cat takes them to meet Sheldon, a tortoise who knows all about friendship. They learn that Sheldon's best friend, a finch is completely different from him and that being best friends doesn't mean you always have to agree.