Today I observed an orthopedic surgeon. He specializes in performing one particular kind of procedure on one particular joint. He does this same surgical procedure hundreds of times a year. And he's good at it. He keeps a detailed database about all of his surgical patients and tracks their outcomes. When an outcome is bad, he works backwards to find what he could have done to avoid it. His modus operandi is repetition and constant refinement. At the operating table, he is comfortable, fluid, and fast.
What I witnessed today epitomizes super-specialization in medicine. Atul Gawande, a surgeon and my favorite medical writer, describes in his extraordinary books Better and Complications how, on the whole, surgeons with the best outcomes are reliably those who have done that procedure the most times. Yet what draws me to medicine is its breadth. Being a good primary-care doc requires a ready knowledge of lots of things, and I think what draws me to medicine as opposed to surgery is the constant variety and the intellectual challenge.
The good news is that medicine is a big tent. Different medical specialties require different goals and temperaments, which makes it more likely that a med student like myself will find something that fits.