Grey's Anatomy, Season 7

Meredith:
[voiceover] Biology says that we are who we are from birth. That our DNA is set in stone. Unchangeable. Our DNA doesn't account for all of us though. We're human. Life changes us. We develop new trades. Become less territorial. We stop competing. We learn from our mistakes. We face our greatest fears. For better or worse. We find ways to become more than our biology. The risk, of course is that we can change to much, to the point we don't recognize ourselves. Finding a way back can be difficult. There is no compass, no map. We just have to close our eyes, take a step and hope to God we'll get there.