I GOT FLU

I have been feeling not well for few days, finally I went to see the doctor after work. I got flu! Not serious though, it's just my throat doesn't feel well and I got sputum, aching back, nausea... The doctor didn't look friendly, his face was black and seems this job is routine and boring for him. I think I saw him not more than 3 mins! How can a doctor diagnose a patience accurately in such short time? I understand why doctors earn so much now! 3 mins for a patience, so if he works 8 hours a day, that means he can diagnose for more than 100 patiences in a day!!