Office Depot CEO Steve Odland remembers like it was yesterday working in an upscale（高消费档次的） French restaurant in Denver.

The purple sorbet（果汁冰糕） in cut glass he was serving tumbled onto the expensive white gown of an obviously rich and important woman. "I watched in slow motion ruining her dress for the evening," Odland says. "I thought I would be shot on sight."

Thirty years have passed, but Odland can't get the stain out of his mind, nor the woman's kind reaction. She was startled, regained composure（镇静；沉着） and, in a reassuring voice, told the teenage Odland, "It's OK. It wasn't your fault." When she left the restaurant, she also left the future Fortune 500 CEO with a life lesson: You can tell a lot about a person by the way he or she treats the waiter.

Odland isn't the only CEO to have made this discovery. Rather, it seems to be one of those rare laws of the land that every CEO learns on the way up. It's hard to get a dozen CEOs to agree about anything, but all interviewed agree with the Waiter Rule.

They acknowledge that CEOs live in a Lake Wobegon world where every dinner or lunch partner is above average in their deference. How others treat the CEO says nothing, they say. But how others treat the waiter is like a magical window into the soul.

And beware of anyone who pulls out the power card to say something like, "I could buy this place and fire you," or "I know the owner and I could have you fired." Those who say such things have revealed more about their character than about their wealth and power.

Whoever came up with the waiter observation "is bang spot on," says BMW North America President Tom Purves, a native of Scotland, a citizen of the United Kingdom and Northern Ireland, who lives in New York City with his Norwegian wife, Hilde, and works for a German company. That makes him qualified to speak on different cultures, and he says the waiter theory is true everywhere.

The CEO who came up with it, or at least first wrote it down, is Raytheon CEO Bill Swanson. He wrote a booklet of 33 short leadership observations called Swanson's Unwritten Rules of Management. Raytheon has given away 250,000 of the books.

Among those 33 rules is only one that Swanson says never fails: "A person who is nice to you but rude to the waiter, or to others, is not a nice person."

Swanson says he first noticed this in the 1970s when he was eating with a man who became "absolutely obnoxious（不愉快的；讨厌的）" to a waiter because the restaurant did not stock a particular wine.

"Watch out for people who have a situational value system, who can turn the charm on and off depending on the status of the person they are interacting with," Swanson writes. "Be especially wary of those who are rude to people perceived to be in subordinate roles."

The Waiter Rule also applies to the way people treat hotel maids, mailroom clerks, bellmen and security guards. Au Bon Pain co-founder Ron Shaich, now CEO of Panera Bread, says he was interviewing a candidate for general counsel in St. Louis. She was "sweet" to Shaich but turned "amazingly rude" to someone cleaning the tables, Shaich says. She didn't get the job.

Shaich says any time candidates are being considered for executive positions at Panera Bread, he asks his assistant, Laura Parisi, how they treated her, because some applicants are "pushy, self-absorbed and rude" to her before she transfers the call to him.

Just about every CEO has a waiter story to tell. Dave Gould, CEO of Witness Systems, experienced the rule firsthand when a waitress dumped a full glass of red wine on the expensive suit of another CEO during a contract negotiation. The victim CEO put her at ease with a joke about not having had time to shower that morning. A few days later, when there was an apparent impasse during negotiations, Gould trusted that CEO to have the character to work out any differences.

CEOs who blow up at waiters have an ego out of control, Gould says. "They're saying, 'I'm better. I'm smarter.' Those people tend not to be collaborative."