What is awesome about medicine to me is a mix of very complicated biology and physiology mixed with the human aspect. It is a challenge to not only know what is best for your patients but understand that they are living breathing human beings as well. You actions (or lack of) have reactions that may or may not be favorable. It is a constant challenge and an amazing field to deal with.
The thing about medicine that I love is that we spend about 7 (or more) years of our lives preparing to give back to our community. The commitment that that involves is amazing. We will not see the actual fruits of our labor for some time. We work hard now for patients that we have not yet even met. That is saying something about who we are.
As cliche as it sounds, one of the greatest things about my clinical experiences in medicine so far is the way you can "help people" and make them feel better, not only physically but also emotionally, during their hospital stay. I had a patient whose face would light up every time I came into the room because I was one of the few doctors/nurses/students that would sit and talk to her for 15-20 minutes. Every day she would tell me, "You are just so nice."
And it's also the coolest thing when one of your patients tells you, "I think you are going to be a great doctor."
And it's also cool to wake up every morning and know that you are doing what you want to do for the rest of your life.