Deciding to pursue medicine can be difficult without the first-hand knowledge of a physician's working life. By shadowing a physician, you can learn about some of the amazing work that he or she does on a daily basis--things you can't learn by taking pre-med classes or watching ER.
In addition to gaining clinical experience, which is important for anyone thinking about medicine, you will develop a close bond with a mentor in the medical field. Take the time to learn about your mentor's interests, specialties, and reasons for why he or she chose to become a physician. Shadowing a physician brings a personal aspect to a pre-med experience that is hard to find elsewhere.