Grey's Anatomy, Season 6

Derek:
[voiceover] Ask most surgeons why they became surgeons and they usually tell you the same thing. The high, the rush, the thrill of the cut. For me it was the quiet. Peace isn't a permanent state. It exists in moments. Fleeting. Gone before we even knew it was there. We can experience it at any time, in a stranger's act of kindness, a task that requires complete focus or simply the comfort of an old routine. Everyday we all experience these moments of peace. The trick is to know when they're happening so that we can embrace them, live in them. And finally let them go.