The man leaps out of the shadows and into the light, a silver blur in a white shirt and violet tie. He bounds across the stage toward his desk, brakes and turns and scampers back stage right, grabs the microphone by its cord and swings it around, letting it thunk on the ground next to his caramel-colored loafers as the CBS Orchestra plays frantically. The audience is on its feet. A fake cityscape frames the man as he hits his mark: a red sticker on the iridescent-blue stage floor of the Ed Sullivan Theater in midtown Manhattan.

The band music ceases, the applause dwindles and David Letterman, jacketless and loosey-goosey, warms up his audience before the the 3,759th taping of “The Late Show.” His color and vigor belies the fact that he’s spent more time on late-night television than anyone, including his idol, Johnny Carson, who reigned for 30 years. Dave passed that mark in February — half a lifetime doing “the dog and pony show,” as he routinely belittles his livelihood.

But.

“But please, I want people to understand: I know it’s not right.”

Any true perfectionist would be suspicious of praise, interpreting it as a misunderstanding of what an art form truly requires, and therefore believing a commendation is really an invalidation. But this doubt, this self-defeatism — it’s all an essential part of who Dave is and what he does. And it’s an essential part of why it’s worked for so many years.

There are those Americans, after all, who want to feel coddled and anesthetized as their eyelids droop in front of the television. There’s at least one late-night program that satisfies this want; it does slightly better in the ratings.

Then there are Americans who want to teeter on the abyss, cackling with glee at the terrible absurdity of life, as they fight off a fitful sleep. These Americans watch Dave. Dave’s the guy next to us on the edge, howling into the void. The show is what keeps him on the edge instead of jumping off it. The show is life.

“Forget everything but the hour of the show,” Dave says. “That’s just it. I don’t like anything — well, I endure every other aspect of the day. But the part of it I enjoy potentially is the hour of the show.”

But don’t read into this too much, into why this isolating admission makes him the perfect host for our millennial anxieties and hysterics. He’ll resist any consideration that isn’t masochistic in nature. He’s slippery, this self-described “towering mass of Lutheran Midwestern guilt,” and tough to hook.

Finally, a desk job