In every day social life, common courtesy is definitely the thing; but therapy is not everyday life.

You would never tell people IRL the intensely private things you tell yr T. Similarly, in that little room there are pressures that come to bear on clients which do not occur in common social life.

There is negative transference, just to take one example, in which the client very clearly perceives in the T, and reacts to it, some hated or feared feature of someone in who actually lived in an earlier life. Is the client to stuff these transference feelings, hide them, even lie about them, for the sake of common courtesy? It seems the derailing of therpeutic work doesn't it?

Maybe this is a question for each client to ask his/her therapist.