It bears illustration.
My filing cabinet sits in the corner of my office, next to my arm chair.
This is the perfect place for it. Not only does it allow me to pretend to be listening to people sitting in it when I'm really staring out the window, but it is situated thus so my ass can gently rest on the arm of it while I do my filing.
Today, however, my chair was not situated thusly. It had been moved. Blame is not important to the story, but suffice it to say a marketing department meeting was had following today's incident. The point is, the chair had been moved so that the right arm of the chair was against the wall and the chair itself was facing the front of the filing cabinet.
I am not a person who notices minor changes to my environment, because I am not a visual person. I am more of a tactile learner. Muscle memory is far more important to my navigation of daily life than visual cues. This is important for the reader to understand, because certainly the first question one will ask upon hearing this tale is "If you face that chair all day, how did you not notice it had been moved?" It doesn't matter why I did not notice the chair had been moved, it only matters that I didn't. So try to focus.
I went to gently rest my ass on the arm of the chair as I would on any other day I go to put away or retrieve files.
As aforementioned, in my mind, all was right with the world and my chair was facing in the proper direction.
I would say that upon being within a milometer of the normal chair arm zone my ass sensed danger.
It was at this point that my mind concluded the chair no longer existed. Being a sleep deprived mother, time slowed down enough that I was able to appreciate a number of things about being human and in the midst of falling. Number one, it doesn't matter how far you are actually falling. It could be three inches or three thousand feet. The fear is the same:
I am about to die.
Number two, when you are falling, your mind is suddenly capable of having approximately 957 thoughts per second.
One of my assistants came to check on me (in no hurry, mind you, as he is quite accustomed to my blood curdling screams) and found me sitting comfortably in the chair, horror stricken.
Despite having to explain to a subordinate why I was screaming in the armchair, this tale has a happy ending. My ass was not gently resting where it thought it would be, but was gently resting nonetheless. The moral of the story is don't jump to the worst conclusions, before a situation has totally played itself out. Also, cut back on the caffeine after the first pot of coffee.