Found in the comments at Winds of Change:

Jim Collins wrote a important book called “Good to Great”, and in it he described a conversation he had with Admiral James Stockdale before he died (yes, Ross Perot’s running mate).

Stockdale was one of the most decorated sailors in naval history. He was a naval aviator shot down over North Vietnam and held in POW camps for over 7 years. He organized the prisoners and kept men alive and sane, including himself. To escape being used as a propaganda tool, he mutilated his own head with a razor so they couldnt be put on film. When they tried to put a hat on him, he used a stool and his fists to destroy his own face. No-one has ever sacrificed more or endured more for his country than James Stockdale did.

Collins interviewed Stockdale about his survival, and he asked him an interesting question: who didn’t survive and why:

“I didn’t say anything for many minutes, and we continued the slow walk toward the faculty club, Stockdale limping and arc-swinging his stiff leg that had never fully recovered from repeated torture. Finally, after about a hundred meters of silence, I asked, “Who didn’t make it out?”

“Oh, that’s easy,” he said. “The optimists.”

“The optimists? I don’t understand,” I said, now completely confused, given what he’d said a hundred meters earlier.

“The optimists. Oh, they were the ones who said, ‘We’re going to be out by Christmas.’ And Christmas would come, and Christmas would go. Then they’d say,‘We’re going to be out by Easter.’ And Easter would come, and Easter would go. And then Thanksgiving, and then it would be Christmas again. And they died of a broken heart.”

Another long pause, and more walking. Then he turned to me and said, “This is a very important lesson. You must never confuse faith that you will prevail in the end—which you can never afford to lose—with the discipline to confront the most brutal facts of your current reality, whatever they might be.”

To this day, I carry a mental image of Stockdale admonishing the optimists: “We’re not getting out by Christmas; deal with it!”

We must confront the most brutal realities and carry on with faith nonetheless. This is now known as the Stockdale Paradox, but it has been faced in every war by every people at one time or another. We are facing it now.

We must confront the most brutal realities and carry on with faith nonetheless. Precisely.