At a dinner in Seattle a couple of weeks ago, a bank official remarked that two major customers had been discussing the area's economic slump, which pushed unemployment in Washington State to 12.8 percent last month. The customers, she said, "were embarrassed to say it, but they had had a very good year."

Her comments triggered a series of similar reports from those at the table. Yachts were selling briskly, one man remarked. Another told of an investment counselor who had just signed off on plans for a $1.5 million house--without a mortgage.

Last week, on another trip, I found myself in conversation with a real estate broker from Greenwich, Conn. "How is business?" I asked. "For houses between $200,000 and $700,000," she said, "it's kind of slow. People aren't cutting prices, but they're having to leave their houses on the market longer. For properties over $700,000, it's terrific."

These are scattered anecdotes--of no significance in themselves. But they provide a counterpoint in a reporter's notebook to the all-too-frequent tales of layoffs and bankruptcies. And they point to a risk that could make the recession itself seem relatively benign: an explosive increase in antagonism between the haves and the have-nots in this badly bent economy.

Almost every place I have been this year, in the East, Midwest and West, local officials and observers have remarked on the extraordinary patience and forebearance of those who are suffering from the economic squeeze. Some polls show that even among those who have lost their jobs, there is a persistent hope that, in the long run, current economic policies will bring the country to a healthier condition.

But in the last few weeks--as I have traveled from California to Connecticut, with many stops in between--there have been more frequent signs of the tension that is building beneath the surface.

For people like myself, who are lucky enough to have good-paying jobs with companies that are prospering, this really has been an easy year. Inflation is down and on big items--like cars and household furnishings--real bargains are available. Meantime, our taxes are being reduced and bankers and brokers compete in offering high interest rates for our tax- deductible retirement savings accounts.

But there is a sense of unease--if not guilt--in our conversations, as with the bank customers who felt "embarrassed" to admit they had had such a good year.

And increasingly, I sense, those who have been run onto the rocks in this economy are getting angry at those who are prospering.

That is part of the drumbeat of derision heard everywhere for the members of Congress who last year voted themselves a quiet little tax break of their own. It is part of the first sharp edge of personal hostility toward President Reagan that I have heard since his election. The comments are scattered, but they are there, indicating that his long-sustained personal popularity may be wearing thin.

But more important--and more worrisome in its potential--is the evidence that this prolonged and severe recession may be twisting the ties of trust and tolerance that hold communities together. In Dubuque, one of the hardest-hit cities I have seen this year, The Wall Street Journal earlier this month reported on the stark contrasts: when a supermarket opened with 55 jobs, more than 1,400 people applied. But a local company developing computer programs for doctors' clinics had a first- quarter profit gain of 66 percent.

There have been more layoffs in my own field-- journalism--than at any time in the almost 30 years I have worked in it. But The New York Times' advertising column reported the other day that advertising revenues are up 41 percent at Town & Country Magazine, which has "repositioned recently as a service magazine for people with money," proving, The Times said, once again, the old tag line, "and the rich get richer."

The Wall Street Journal headlined another story, "Games, Other Luxuries Sell Well As Slump Slows Sales of Durables." Bank profits were up 20 percent over the previous year, in the first quarter, the paper said. But another story reported that more than 600,000 workers are within 13 weeks of losing their unemployment benefits--unless Congress votes an emergency extension.

Meantime, another tax cut approaches on July 1. According to the Joint Committee on Taxation, the 31.7 million tax-filers making $15,000 a year or less will divide $2.9 billion in savings; the 162,000 making over $200,000 will split $3.6 billion.

The favoritism to the rich inherent in these flat- rate tax cuts was justified on the grounds that they would stimulate the economy and produce jobs. But since the program was put into place, economic differences and social tensions in America have increased-- and so has unemployment.

That is more than an economic calamity; it is a recipe for social disaster.