Good Morning

I am NOT a morning person.  I am a night owl.  Always have been, always will be.  That's not going to change.  I am tired when I wake up and it takes me awhile to get moving in the morning.  I can be polite but brief with people.  I try to schedule meetings if possible after 10am.  I need to get coffee and clear my head.  I typically start my work day with simple non-thought provoking tasks first.  Sometimes this is an issue as it was recently in my office.  There are some employees who start much sooner than I do.  They may have already been at work up to 2 hours before I even walk through the door.  Needless to say, they are morning people.  One in particular followed me into my office recently one morning.  I hadn't even put my stuff down or unzipped my coat.  Just shoved a cell phone in my face to look at a picture.  Not work related, personal.  I sort of mumbled an uh huh and left it at that.  Well the next day this employee actually confronted me over this.  Asked me if I had a problem with them or if I was just in a bad mood.  Well instead of saying exactly what I felt which was what did you think my response was going to be when you jump on me as soon as I walk in the door, no I was the bigger person and said that I had a bad morning and was running late and it had nothing to do with them.  Now this is the same person who also then leaves 2 hours before me and if I dare try to present something WORK related, not personal any more than a half an hour before they leave, I get a nasty response.  So obviously this person doesn't do well in the late afternoon.  But that apparently is okay behaviour.  By the way, I would be more senior than this person so that behaviour could be insubordination.  I guess I am just tired.  Tired of people and just plain tired tonight.