 This Entertainment Insider is sponsored by Progressive Insurance. It's been 25 years since SpongeBob SquarePants made its debut. Tom Kenny, the voice of SpongeBob, knows why fans still love it. If SpongeBob was nothing but optimistic, that wouldn't be a very good show. So SpongeBob does get down in the dumps. SpongeBob does get discouraged. SpongeBob does feel sad, but he bounces back.