Worse, yesterday I was in my "mind palace" long enough for one of my new coworkers to come up to me with a look of concern and ask if I was all right. We had just finished CPR training and I think he might have been afraid he was going to have to put it to use. On a couple of occasions, I only snapped out of my mental planning when someone walked into my room. Thankfully, each time was enough of a push for me to get a little more done.
The worst times are when I shake off my thoughts only to realize that someone was directly in the line of sight of my blank stare, and they see me. Usually they realize that I am not doing so consciously, but sometimes I think that people get the wrong idea. With this in mind, if I know I am going into such a trance, I try to pick a spot on a far wall or a piece of paper that I have in front of me. That doesn't help when someone moves into my sight line.
Yet, for all of the possible awkwardness, there is something refreshing about taking that type of mental journey. With the distractions we have around us and the availability of mobile technology to entertain me, I do not go on these mental journeys frequently as I probably should. It's important to focus inward from time to time.
... As long as I'm careful about where I'm staring.