Why doctor, why?

Well this thought suddenly got its way into my mind. All of the sudden. Why doctors always use complicated terms for sickness' or diseases?

1. It sounds cool.
2. It's hard for the patient to get the presciption anywhere else...only the doctor know the correct spelling or pronunciation of meds and diseases.
3. Well, lets face it, patients will get insulted with direct english or other languages with the same meaning as the medical terms. EG: Schizophrenia - crazyness; Doctor: You are crazy, mister. Patient: What did you call me??!! Arrghhh! *kills self*

By the way, my dear room mate is now in a Psyciatric Ward. Gosh crazy people's ward! Me: Arrrgh! God save me from crazy people...I'm gonna be in their ward soon! Arrghh!