Luckily, as a pre-dental student, I had free rein to choose any major I wanted as long as all the prerequisite courses for dental schools were complete. So why math? Well, I've always enjoyed math since high school (HS). My favorite course in HS was Geometry, especially the proofs section (i.e. given an object, prove it is a certain shape).
The more abstract, the more my mind was captivated by the subject. Since Pure Mathematics is the branch that is more concerned with proofs than calculations, I knew that is the major for me. My absolute favorite subjects were Abstract Algebra and Number Theory. I pondered the question above for over 24 hours. Once the epiphany came to me, it felt like a wreaking ball tore down my mental block (notice lines of the bricks represent the grooves of the brain).
Mathematics was a fun hubby and studying math improved my critical thinking skills. As a future clinician, it is vital to have great problem solving skills and being able to come up with the correct differential diagnosis.