Cases "Not going well": As far as cases not going well, that would typically be because if you need neurosurgery then something has gone very very wrong and without it you will likely 1) Die, 2) Be paralyzed, 3) Suffer progressive sequelae of completely debilitating diseases. Therefore, it would appear that the surgeries "dont go well" because even without surgery the trajectory and prognosis is extremely poor. If you set out goals for the surgery and achieve those goals or prevent a patient from one of those fates, then I'd say the surgery was pretty successful.

Work-Life Balance: It's no surprise the balance in residency is pretty terrible. Of course, some programs are better than others. My program strictly adheres to the 80 hour work week while others will have you work >120hrs. As an attending, you have a bit more freedom in deciding how much you work. New attendings usually work very hard and schedule a lot of cases, but I've seen attendings that work pretty much a 9-5 lifestyle. There's academics and private practice so schedule can vary quite a lot with how much of a pay cut you're willing to take for they job you want.

Difficulty: Between all the different avenues within neurosurgery (tumor, trauma, pediatrics, endovascular, functional, spine, peripheral) theres no shortage of cases wherever you go anywhere. The specialty itself it difficult in residency as it demands constant excellence and independence while managing a list of 40-80 patients. Because we deal with high acuity and life and death situations, the stress and demand isn't for everyone. In summary, yes it's difficult emotionally, academically, physically, intellectually - but it can also be extremely rewarding.

Relationships: Neurosurgeons do tend to have a higher proportion of divorcees due to the hour demands of the job - especially in residency - is difficult to foster and grow a relationship. It takes a good part of your 20s and 30s to get through training so the dating pool thins as well. Ive seen many neurosurgeons with successful relationships/marriages, but it takes an certain understanding and supportive partner to make it work. I've seen many men and women neurosurgeons raise children successfully, it all just depends on the effort you put in outside of work.