Although I find some aspects of medicine fascinating, I suspect I'd hate being a doctor.
I'm not great at dealing with blood and viscera, but I could learn to get beyond that aversion. The real problem is that people would seek my assistance with a potentially life-threatening illness (diabetes, for example), and then after I shared my expert advice with them on what was necessary to save their lives, they would leave my office and refuse to take enough responsibility to do what they need to do.
Hell, I already have people coming to me for advice on matters that AREN'T life threatening (how to secure their home Wifi access points, for example)-- and then completely disregard what I tell them. It wastes my time and seriously annoys me, and people's lives aren't even at stake, so can you imagine how righteously pissed I'd be if I were a doctor?