[quote=Nightrunner]
I actually do the exact same thing. I find myself arguing both sides of a point surprisingly often even when I'm only looking for one result. I was actually discussing chemistry/anatomy/physics with myself yesterday when I was in the store. Before realizing I'd been staring in a mirror talking to myself for five minutes.
[/quote]

Thing is I don't even look at a mirror or anything. I could just be, say, walking someplace and just have a conversation as if there's someone walking next to me - except significantly more quietly, and also I'm semi-aware that there's no one there. ...It's weird.