Right Brain vs. Left Brain

So I decided to Google 'Optical Illusions' today, just for the heck of it. They're always fun to look at, and to see how much they can really mess with your eyes.
But one I found messes with more than your eyes, seriously. It messes with your brain.
Go to links at the right, and pick the "Dancing Illusion".
It's wild. It says on the website that for most people, the dancer will be circling counter-clockwise. I found that I could make it spin either way though, pretty much on a whim. Whenever I started thinking about math, it spun to the left. When I thought about emotions, like love, and relationships with friends, it started spinning to the right.
So, is this just me? Or can I just grasp really well how to use both sides of my brain? I know it sounds crazy, but I think I literally was staring at it for twenty minutes, just trying (and succeeding) at making it reverse the way it spun.
I'd be interested to know others' results from this optical illusion. Are you able to make it spin the opposite direction at will?