I take it to mean, in the song, that it’s so jubilant and happy that it’s all sunshine.
Nothing dark and nefarious. It’s just a song about being happy, what’s so wrong about that?
Nothing at all! I love the song, and I have an adorable short video of my 2-year-old grandson rocking out to it. I corral everyone I meet and make them watch it. ;-)
However, the room will be wet.