Contrary to what you might think about witnessing death is not the worst thing, as long as the doctors have done everything that was in our hands, because we understand death as a natural part of life's cycle. Of course if patient is very young it hurts to every medical team.
Since I started studying medicine the worst things have been:
1º so many hours of study.
2º finish the Medicine Grade and feel responsible for the healthcare of others without having had practical experience (the law obliges)
3º To know that I have to continue studying.
4th. Knowing that I will always feel some insecurity because Medicine is huge and I can never know everything at the moment.
The best things since I started (not in priority order):
1º To learn so much and to understand how we work.
2º To know in reality how people is trough listening them, to know different patients and to see different lives by their histories.
3º Keep learning and meeting doctors who are wonderful and teach you everything they know.
4º To feel useful and to be able to help to live better.
5th Knowing that studying so many hours reduces the risk of dementia XD
6º To know that every day I am going to learn something new for sure.
7º To grow up, to get patience, to understand feelings I ever had.
8º Something that happened to me: to realize which friends love you as person and which others love you 'cause you're doctor!
9º Being part of middle-class of the society, you can earn money in every country you travel to.
10º I thing the good things list can be infinite.
If you're interested in becoming doctor I can confirm is hard way to become a professional but it worth it from every point of view. I hope you feel answered with this. Please, feel free to ask me any doubt you wonder.
Regards: M. López-Aragó