It's 6 p.m. and the customer has mutilated his parking stub. Maybe he has nibbled on it. Anyway, the ticket will not clear the computer. Everybody else is honking and blowing exhaust fumes into the night sky. The customer calls you a "stupid head" or worse. He tells you the airport is a ripoff, life is a ripoff.

You try to stay cool. You are not a dumb person. Not all your customers are nasty, you remind yourself. Traffic at Dulles International Airport is booming, and the Federal Aviation Administration is considering increasing the parking lot exits, with your hearty support. In the meantime, you wish you could ask people to slow down. Mellow out. Have patience.

Sue Twitchell is general manager for International Business Services at Dulles, which means she oversees the parking lots. She grew up in Japan. Rudeness is not part of her heritage. When the airport is really congested, as many as half of the 5,000 drivers who clear the main and short-term lots each day have something memorable to say to the attendants.

"They're more than rude," said Twitchell. "They're vulgar. They cuss you right out."

Look at it from the attendants' point of view. There are 17 of them, and they work three shifts -- morning, evening and midnight. Some are housewives. For others, this is a second job. Some attendants live as far away as West Virginia. They like the job. Mostly, people are mannerly. It's only in the late afternoon, when the cars start piling up at the gate . . . .

Twitchell says she tries to sympathize with the angry customers. They're back from a business trip that went sour. Or the airlines lost their luggage. Or they parked in short-term when they meant to park in a less expensive satellite lot. Of course, they didn't see the signs.

They never see the signs. Occasionally, they threaten to report the attendant to higher-ups. They write letters. They say they have "friends in Congress." They complain that they used up half a tank of gas waiting in the parking lot line.

Usually, Twitchell tries to ignore it. "They just like to show you how big they are, but in my book, the bigger they come, the smaller they are." If she's really exasperated, she might say: "Mister -- give me a break. I cannot even find those words in my dictionary."

Maintaining her calm is a challenge. She tells her parking lot attendants that they're the last memories anyone has of Dulles. Twitchell advises them to say "Have a good day" and "Drive carefully, now." Still, the insults continue, and the me-first stuff is sometimes appalling.

"I've told my husband many, many times I wish I had the brains to write a book about this parking," she said.

Customers are especially grouchy in the winter, when they have a dead car battery or they haven't warmed the car up. Also in the summer, when the car air conditioner isn't enough to chill Washington's back-soaking heat.

In the spring and fall, they're more likely to sing to their radios as the customer at the booth searches his glove compartment for a ticket, or another counts out $1.50 in pennies. They aren't as antsy when a member of Congress takes a few minutes to fill out the chit that exempts VIPs from parking fees.

And the customers are pretty pleasant in the mornings, when few flights are coming into the airport and the lanes leading up to the toll booth are wide open. Mornings are when J.E. Solomon works as an attendant. He's a 70-year-old ex-dairy farmer from Leesburg, Va.

One recent day he sat in his booth reading "Pocket Proverbs -- Wisdom to Live By" while waiting for customers. "If I live until the first of May," he said, "it'll be 22 years for me here at the airport." His only complaint is that car rentals have moved out of the main lot. "I had a lot of friends -- all those rental boys driving through here."

Most of Solomon's customers are, as he says, "pretty accommodatin' to you." When they do cuss him out, he tries hard not to take it personally. "It's like the old saying -- it takes all kinds of people to make a world. And you don't know whether they might have dope, or some kind of a problem at home."

Helen Leake, a 42-year-old woman from Berryville, Va., also works the day shift. She says nobody has ever sworn at her. "They'll swear at the airport, or at the parking fees. They'll say, 'What's this country coming to?' " Leake never takes it personally. She loves the job, working with the public. "We try to take one car at a time, then go on to the next," she said. "You can only do what you can do."

Martha Noakes is 48. She's from White Post, Va., near Winchester. Noakes took the job last April. "All my kids had grown up, and it was boring at home. So I said, 'What the heck, I'm going to find me a job.' " After so many years as a housewife, the job came as sort of a shock. "I didn't have any idea that people were so rude," she said.

Her worst times of year are Thanksgiving ("murder") and Christmas, when the airport is flooded with travelers. "They yell at you and call you stupid. And then your machine malfunctions, and they really think you're dumb -- that you never knew what you were doing in the first place. And it's always us. It's always the cashiers that are doing all the bad things."

Maybe Noakes is used to it, but the insults don't bother her anymore. In one ear, out the other. "Have a nice day." "Drive carefully." She just wishes that Dulles customers understood all the tiny headaches that can slow a parking line. Lost tickets. No money. Somebody needs directions to Rte. 50, or to the Washington Monument. "You'd be surprised at the people who ask me, 'Where am I? Where do I go now?' "