Multisys stuff
Multiple systems is a little Like having an imaginary friend, and for a long time can seem like exactly the same thing.
The weirdness starts when you get frustrated, or you're tired or angry and all of a sudden the person you're used to considering You falls asleep or passes out and the only person still awake in the body is, well... Your imaginary friend.
And she's You, now. Or more appropriately, she can now operate as if it's Her body.
And this can take some getting used to, especially when your friends start asking why you're talking like that.