This job can make your brain hurt. Brain surgeons normally get around four weeks off a year. The rest of the time they are opening up heads or conducting spinal surgery. It is not rare for a brain surgeon to work over 60 hours a week. The problem is that this is a very specialized field of medicine. Sure, there are tons of doctors, but not very many people become brain surgeons.
Maybe it is the 16 years of training that does it. The stressors involved in neurosurgery are innumerable. Some of this stress is due to long hours at the hospital, events in the operating room, publishing academic papers, dealing with insurance companies, handling any lawsuits, maintaining a life outside the office, and staying relevant in the ever-changing world of neurosurgery. But mostly it's about trying not to kill people.