I don't know if I really "left" if I never joined in the first place. I'm almost a doctor, now, but I studied computer science in college and became pre med in my third year of college.
I realized I didn't really want to be a cog in the wheel without human interaction, and I wanted the perspective one gets in medicine to be able to come up with solutions that help people. That evolved while in school to building software/hardware that increased access to medical care, and it's been a cool ride trying to figure out how to actually come up with studies that prove my ideas work (or don't). It's also extremely gratifying to treat patients and make them better, even if it's at the micro scale.
I realized I didn't really want to be a cog in the wheel without human interaction, and I wanted the perspective one gets in medicine to be able to come up with solutions that help people. That evolved while in school to building software/hardware that increased access to medical care, and it's been a cool ride trying to figure out how to actually come up with studies that prove my ideas work (or don't). It's also extremely gratifying to treat patients and make them better, even if it's at the micro scale.