you have to have enough experience with the medical world,
dedication to it as a profession (profession is fundamentally different than job, and implies a fiduciary duty, meaning a LEGAL duty to act in someone else's best interest even when it conflicts with your own),
it's a calling,
it will frequently have to come before anything else in your life.
you need a love that borders on addiction I think it find it "worth it"
meets the most basic definition of addiction:
"continued use/pursuit in the face of increasing harm"