Viewpoint

How does David Letterman feel about his new ratings success? How does David Letterman feel about being on the Phil Donahue show? How does David Letterman feel about show business?

Aw, who cares how David Letterman feels about anything?

You care, that’s who cares, because you’re a caring person. A card-carrying caring person. You want to know David Letterman’s innermost thoughts, especially now that his show, “Late Night with David Letterman,” is enjoying its best Nielsen numbers ever, and just as it celebrated its third anniversary too.

“This ratings thing is very mystifying to me,” says a worried Letterman, the Bob Hope of the hip, from his cluttered Manhattan office. Letterman was recently told by NBC Entertainment President Brandon Tartikoff that his ratings are up 25% over last year. “I don’t know what happened,” Letterman says. “We’re not doing anything different on the show. It’s a mystery. Actually, I thought we were doing better shows in some ways in our first and second years.

“Maybe we’ve just worn people down. They just say ‘Oh all right, we’ll watch your darn show,’ ” says the pessimistic prankster. Since he doesn’t know what made the ratings go up, he can’t do more of whatever is responsible. Anyway, euphoria is not his normal state, so he’s not going to get giddy about high ratings. “They’ll probably just go right back down again,” he sulks.

Unpretentious, undemonstrative and unimpressed with his own success, Letterman has carved out comedy territory that is all his own. But that may be because no one else wants it. He drops watermelons off 11-story buildings, crushes Barbie dolls under steamrollers, rails against the injustices perpetrated by cable-TV systems and threatens to sue guests who don’t show up on his program for $1.5 million, minimum. He is clever, sly and wittily wacky, and now he’s what he probably most feared he might become: a mainstream television hit.

And through all this he refuses to turn into a big TV creep. “The longer I’m alive, the more I hate show business,” he says. “Every time I go back to L.A., which I just did, I say to myself, ‘This is the silliest, stupidest way in the world to make a living.’ ” But then he knows he wouldn’t make more than $1 million a year as a Mercedes Benz mechanic.

One of Letterman’s frequent guests, Jay Leno, comedian and ombudsman at large, once was a Mercedes Benz mechanic. How about that?! And he says of Letterman, “David knows exactly what he does. Like, the funniest thing in the world is when I see David ‘act’ on his show. Like when he’ll do a bit, and say something like, ‘All right, put the gun down.’ I get hysterical! I call him up and say, ‘Wonderful acting job!’ ‘Cause, see, a lot of people in show business don’t know their limitations, and they always try to go over them, and it looks clumsy, but David knows exactly what he does.”

Crazily inventive and yet studiously cautious, Letterman doesn’t like to venture outside his chosen turf. When he did the Donahue show recently, he hated it. “It was so bizarre, my heart sank. I just wanted to go home.” And when, after a recent “Tonight Show” appearance, Johnny Carson asked Dave if he wanted to come over to Johnny’s new Malibu beach house (it’s one acre inside ) and play tennis, Dave freaked out. “I realize I was terrified of actually spending time with him,” he says.

For the third anniversary program, Letterman and company staged a “Late Night Baby” contest between two New York hospitals. The first baby born during the taping of the program would be declared the “Late Night Baby” and, says Letterman, become “the wealthiest, most powerful child in the world.” Before the show, Letterman was asked what would happen if the mother didn’t want this particular honor. “Then we’ll flash her a $20 (bill) or two,” Letterman said confidently. “We’ll change her mind.”

On “Late Night,” however, it’s not anything for a laugh. They have never destroyed an entire American town, for instance. Leno admires the way Letterman refrains from “sneering sexist humor” about such topics as Dolly Parton’s breasts. And Letterman does have his standards. Asked why he refused to try on a wig offered him one night by guest Eva Gabor, Letterman says, “We have kind of a rule of thumb on the show: I don’t wear funny headgear. I feel like I look like a jerk to begin with.”

Looks may be deceiving. Letterman presides over the brightest loony bin in all of television.