While every profession has its own challenges and stressors, and while I do not have any personal experience in any other profession, it's pretty fair to say that medicine has some unique stressors that may weigh more heavily on people's emotional, mental, and psychological well-being. Patients dying, either from something you did or something you didn't do or because it wasn't possible to help them. That's a huge burden for someone to bear. We had a talk this past week from a physician who broke down crying while talking about a patient who passed away years and years ago. That stuff stays with you. Some people grow stronger from it, some people break down bit by bit.
Long hours, lack of time with family/friends, the years of studying and being beaten down emotionally in med school (and residency?). I don't know what year @Planes2Doc is in school, but I pretty much agree with everything he's said. There were so many days in my first 2 years of med school that I just wanted to give up. I asked myself what I was doing here and why I was doing this to myself. There are parts of med school that I really enjoyed, but those were mainly social and extracurricular things, as well as our weekly clinical sessions where we got to work with doctors and see/interview patients. The academic side of med school until now has been pretty miserable to say the least, but I think those weekly clinical sessions were what gave me hope that I'll enjoy the job that's at the end of all of this. I'm really looking forward to clerkships, and while I know 3rd year brings its own challenges, I've heard from countless upperclassmen that it's a great time.