Supernatural, Season 6

Death:
Today, you got a hard look behind the curtain. Wrecking the natural order's not quite such fun when you have to mop up the mess, is it? This is hard for you, Dean. You throw away your life because you've come to assume that it'll bounce right back into your lap. But the human soul is not a rubber ball. It's vulnerable, impermanent, but stronger than you know. And more valuable than you can imagine. So, I think you've learned something today.