I live to please, so here are some thoughts that swayed me from one specialty to another. Keep in mind that these are thoughts that I had regarding specialties that applied to ME and may not apply to you.
Family medicine: I liked the concept, with regular patients and continuity of care. However, I didn't like taking care of kids, and I didn't like the extreme breadth of disease.
Pediatrics: I don't like taking care of kids. When a 72 yr old diabetic has a heart attack and dies, it's unfortunate, but at least I can console myself and say he had a good run. When a 6 yr old dies, that invariably falls on me. Peds deals with a lot of genetic diseases which are rare, but you can't afford to miss. I hate genetic disorders. Peds has parents. I hate parents.
Psychiatry: while I didn't enjoy adult psych, I really loved child psych. I thought the kids were so precious, and I was absolutely struck by the tragedy of their cases, and how for so many of them, their only fault was being born to shitty parents. However, in the end, I couldn't take the tragic nature of the field.
OB/Gyn: I really liked Gyn. Relatively healthy patients, limited number of interventions, good split between clinic and surgery. I thought it was really neat. The OB part I could've done without, but nothing trumps introducing a mother to her new baby. But so many women didn't want anything to do with me because I was a man, and I wanted to make more lasting connections with my patients.
Surgery: Wow, fun. I really enjoyed the technical nature and the quest for excellence, but the bedside portion was so pitiful. We would do a hemicolectomy for obstruction from metastatic colon cancer, and never talk to the patient about their abysmal prognosis. I didn't want to 'sign off' of a patient who needed help.
Anesthesia: 99% boring, 1% terror. Hate boredom. Hate terror.
Dermatology: I loved derm. L-O-V-E-D. Office procedures, almost entirely outpatient, as much continuity as I wanted, get to see some bizarre and unusual disease mixed in with simple but fulfilling care. If I had the board scores for it, I would've done derm, but I'm just not that smart.
Radiology: Zero direct patient care. No thanks.
Neurology: All diagnosis, no treatment.
Pathology: The most scientific of all specialties, the greatest arbiter of diagnosis, but the only time I get to work with patients is when they're dead. While I loved the science, I wanted to see patients.
So in the end, I went with internal medicine. I loved the diagnostic challenges, the continuity of care, the limited focus compared to family, the treatment aspects, and the attitude. Internists are generally somewhat anal-retentive folks, and a little OCD. We obsess over tests and meds and things like sensitivity and likelihood ratios. There is a constant fight between the art of medicine and the science. In adult care, we are management kings.
But also, we are a dumping ground. We admit patients spurned by every other service: Gyn, neuro, surgery, when everyone else passes, the patient goes to medicine. While I find this aggravating, I also feel that someone has to look out for the patient.
I came to peace with this fact when I talked to a US Marine a while back. I was marveling at his bravery, enlisting in the branch of the services known for being the first to fight. You don't join the marines to avoid war; you join to get your hands dirty. Rather than be proud of his service, he completely downplayed it. "Y'know, when there's a job to do, someone has to step up and say 'I'll do it.'"
And although I'm not in the military, this is pretty much my attitude towards internal medicine. I did not become a doctor to avoid work. I became a doctor because I felt that I could do some good. And whenever people complain that medicine is a dumping ground, my reply is always that there is a patient who needs help, and if no one else will step up, I will. I have even been so bold as to tell other doctors if they don't want to do what's right, then I will.
And when I die, I hope that people won't say what I nice person I was, or that I'll be missed. What I want people to remember about me is that when I was needed, I always answered. I did not become a doctor to rest on my laurels. I came to work.