While therapists are not (fortunately for the one I pay) mind-readers, they should certainly be used to and able to handle clients who are anxious, stressed about being there, and who have difficulty talking. I do not expect that a therapist is all that baffled nor going WTF when a client has these sorts of challenges. Further, it is not the job of the client to worry about or put themselves in the shoes of a therapist. The therapist should be trained to handle such things and no client should have to feel ashamed or worried about the therapist.
Also it is not the same as expecting a mind-reader.