Insanity??

I've been thinking a lot lately about what exactly constitutes insanity. Is it when you're walking to the bus stop carrying your shoes and talking to yourself?? Or is it when you waltz alone in your living room to Doug and the Slugs?? Or is it that little voice that you hear late and night, saying 'Is there room in your head for one more?? Or perhaps it's forgetting to eat for three days, or maybe realizing that when you sync it up right, Dark Side of the Moon seems like it's narrating The Wizard of Oz. Or perhaps it's talking on the phone while sitting on top of the washing machine. Or maybe it's when the person on the other end hangs up and you still sit there, listening to the dial tone for half an hour, thinking of nothing.
And who gets to say, really?? I mean, sometimes you have the more definable types of insane, like schizophrenia, but even that can be iffy sometimes. What if someone just seems schizo, but really they're just lonely?? Or maybe trying to get attention?? Don't get me wrong, I'm not saying that schizophrenia isn't an actual condition, because it is. I'm just saying that things aren't always set in stone.
So, what do you think?? What's your definition of crazy??