The first morning after foster Bailey arrived she would not let me in the doorway to her room. Had she continued that behavior for very long she would definitely have been on my "afraid of" list. Even though I do not fear being in the room with her, IF I would ever actually have to DO something to her that she would not like, I am sure I'll be scared to death!!!
And, as far as grooming customers go, there have been a few we sent away because we were too afraid of their behavior to work on them.