You see and treat patients in an emergency room, between the incredibly sick and the not so sick. You are expected to know and treat a wide variety of disease processes and have a sound understanding of medicine
Getting to treat and help people during their time of need. Its constant variety in the types of people you see and the problems they may have. Also, after your residency training you essentially only work on average 12-14 days in a month usually at 8-12 hour shift lengths depending on your job.
It is a consistent grind of work. The huge volumes of patients at times may become burdensome. It also takes a long time to become an EM physician so a lot of delayed gratification. The job can also be very stressful when you have someone incredibly sick or if you have multiple people who are sick. You also have to go through residency training, a grueling training process usually 3-4 years where you are working 60-80 hr work weeks.