Psychological Mishap

So I've taken lots of "quizzes" in my life, from the silly, ill-written Facebook "What kind of dog are you?" to the more serious Meyer-Briggs. What I have seemed to find is that each is based upon a presumption that there exists an "true self," deep down, or wherever it is. One difficulty psychologists face with all sorts of personality "tests" is the inability to make sure the person taking the test answers the questions "truthfully" (how one really reacts, feel, etc.) instead of how wishes she reacts, feels, etc. After recently taking one such test, I noticed that in my attempts to be "truthful" I was really quite negative (aftermath of a certain Christian upbringing), and as I went along, I felt myself slowly think horrible things about myself, began to hate myself, and then assumed I really would, if I was "truthful" or something, choose to preserve myself over others, or use others for my own purposes. I then began to wonder if this attempt to be "truthful" was actually working to make me this way. All in all, I've begun to think that mabye there is no real, isolated self to be "truthful" about. Maybe we only have choices.