I picked it because I fell in love with it. You get to make quick, very important decisions with instant feedback. You don't sit around and talk about what you are going to do for an hour on rounds, and then see what happens over the next few days. I love being in the OR. I love that when you are done for the day, you are done. No calls in the middle of the night saying that your patient is in pain. I love the brief, intense relationships you make with patients. Although under appreciated, I love how truly vital you are during an operation. I also love the hands on, procedural aspects of anesthesia.
I was torn between anesthesia and surgery. I'm still yet to meet an anesthesiologist that doesn't love their job. I've met way too many surgeons that say they would do something different if given the opportunity (funny how many say they would pick anesthesia).