"My wife, she says, 'God help us all if there's a time when you don't have a show.' And my (physician) father says, 'You're making a living off of something that probably should be treated.' It's just my nature not to celebrate things, but rather treat them like I've just been given this huge responsibility. So if anything, I like to save those 'Yippee!' moments for the camera."
Those moments are nearing. Helping share the spotlight for O'Brien's debut as host of The Tonight Show will be the band Pearl Jam and his friend Ferrell. That'll help ease the nerves. But it won't erase O'Brien's comedy-generating angst.
How deep does it go? He'll gladly demonstrate.
"Come this way," he says, rising from his office chair. A few long strides later, O'Brien wheels into his dressing room, a nondescript box save for a large, black-and-white framed etching that hangs on one wall.
In it, a group of men gather around a dead President Lincoln.
"I've always practiced my monologue in front of this image before going on stage," O'Brien says. "Looking at that, I figure, heck, it could always be worse."