The doctor -patient relationship is complex one. A lot of factors come into play. These are to do with doctor's own personality, family background, workload, work environment etc. Also matter the patient's background, education, etc Mostly it is to do with workload and to some extent the patient's repeated silly questions which needs common sense and not medical knowledge to answer. When confronted with such situations just nod your head rather then give a rude reply. In my opinion rudeness should be avoided at all cost.