When outpatient service, why do most doctors in public hospitals not treat patients who have been seen by doctors in the same department?

Of course, patients who have just seen doctors from the same department will not be treated if they come to see a doctor, just to avoid suspicion. Moreover, patients who have just seen a doctor and then go to the same doctor are more suspicious, and their illness is not easy to be cured (psychological effects on health, see "Huangdi Neijing"), and it is easy to cause disputes. Since ancient times, there has been a saying in China that apricot trees cannot be cured by those who do not believe in doctors.