I've been thinking about Pinky and the Brain lately (you know, the lab mice from Animaniacs that got two spin-offs of their own). I've got a theory about the true meaning behind their theme song.
I think that Pinky is truly the genius and Brain was the insane one. Let me explain.
Geniuses don't generally want to take over the world. Geniuses have odd thought lines that don't make sense to non-geniuses (or other geniuses). Pinky generally managed to blow Brain's plans for world domination without trying.
Brain however came up with more and more insane sounding plans for taking over the world. And even though he kept failing, he kept coming up with new plans. He kept repeating the same types of actions over and over and kept expecting a different outcome, which is a popular definition of insanity.
That's my theory. Make of it what you will.