Medical school is an abusive environment. It's literally filled with awesome people like hypercompetitive assholes who you will throw you under the bus, professors whose teaching method consists of socratically asking you questions until you look like a moron in front of your peers. Public humiliation was a daily experience and physical abuse was also not unheard of. Soul destroying work schedules are also imposed on you even while you're still a student. In fact, this labor is straight up integrated into the system. Students can't do much because they don't know anything but residency is comparable to indentured servitude.
It's hard to describe the effect years of this can have on the mind. Things can get so distorted you feel guilty for eating, for going to the bathroom, sleeping, resting. Normal people things like a weekend or a good night's sleep become luxuries to you. You come home and everyone's already asleep. People start out all starry eyed and thinking about making a successful career out of helping people, but as it nears its end people can't wait to just start making fat stacks already.
It functions as a sociopath breeding ground. Basically weeds out your humanity by punching you until you like it, hammering you until you get good at it so that you fit into the system. Some people just quit when faced with that, others try to take it and end up committing suicide. One of the most haunting stories I've ever heard was about young woman asking her attendings about suicide methods after a patient killed himself. They thought she was an interested student who was trying to learn about stuff so they happily dispensed all the information they knew. She efficiently and painlessly killed herself not even a day later.
People who make it out of this process might enjoy good pay and lifestyle depending on the country and the specialty they chose. It definitely costs them, though.