1. Dealing physically and emotionally with the suffering of other human beings.
2. Lack of adequate support from management.
3. Inadequate training for all aspects of the job and lack of support for ongoing training (healthcare practitioner must participate in life-long learning).
4. Lack of fairness towards all people in the USA regarding ability to seek and receive healthcare.
Here's a story. I was a registered nurse working in one the of the biggest hospitals in the USA. My specialty is cancer nursing. We had a late evening admission of a newly diagnosed leukemia patient, and the guy was acutely ill. And dirty. He was a homeless person, straight off the street. Before I could administer medications or other "physician ordered" things, I had to get this guy clean. He was so weak that he couldn't help me do this. I pushed his wheelchair into the shower room, and got into the shower with him. It took a while as I recall, but afterwards he smelled fresh and it was safe for me to start an IV and get the medications going. You see, people with leukemia have damaged immune systems and even dirt on their own skin might make them ill.
This man, because of lack of health care equity, couldn't get into the medical system until it was nearly too late. No one trained me to get into a shower to clean a homeless man: I improvised. They way he looked and smelled almost made me physically ill, but his gratitude after the shower made up for my discomfort.
I hope others answer your question as well Markell!