I was in "Kelsyland."

I have a history of leaving the present and escaping into my mind.  This may happen to some of you.  Yet, I feel like it manifests itself in me differently.  When I was younger, I used to be sitting at the dinner table with the rest of the family, when all of the sudden, my lovely sister, Kristen would say, "Who are you talking to?"  Of course I would respond embarrassingly, "no one."  She would then say, "You were nodding your head and making facial expressions to no one?" Yes I was.  My father also loves to catch me in one of these moments, and somehow he gets me to tell him who I was talking to and what I was saying.
I've come to realize I can be very animated when having an imaginary conversation with someone in my mind.  Usually this exists of someone I would like to say certain things to, but am too afraid of the confrontation, so I just do it in my head.  Have you experienced this?
Well, the other night at work I had a situation like this.  I was sitting at the nurses station, and had just finished my patients pre-op check list.  Somehow I slipped into "Kelsyland" as I fondly refer to it, said a few things to a co-worker, probably made a few nods, maybe raised an eyebrow or two, when I was interrupted by another co-worker saying, "whatarya doin?"  She proceeded to tell me she thought I was staring at a computer screen, then realized there was no computer screen there and figured she better break me from my trance.  I turned bright red, and tried to downplay my embarrassment by saying that I was just dazing off, you know, it's the middle of the night, I'm just taking a nap with my eyes open.  She responded, "Yeah, it just looked like you were talking to someone, but no words were coming out of your mouth."
The bottom line is that I was talking to someone, in my head.  Don't worry people, I don't hear voices in my head, this is not some psych issue, I was merely practicing a conversation with someone so that if it actually happens, it will be well rehearsed.  Nonetheless, it's embarrassing.