People read this off very small evidence. How you speak to waiting staff. Whether you look up when somebody comes into the room. What your face does in the half-second before you answer a question you have been asked twice.
None of that is projected on purpose, which is why it cannot be performed for long. Anyone can manage a pleasant hour. What leaks out is the accumulated habit underneath, built from a thousand unwatched moments, and almost everybody reads it accurately inside ten minutes.