Computers get their revenge.

It's summer. Vacation season. Time to relax. Yet, nearing the end of your week-long escape from the office, the thought hits you: You'll go back to mail piled high on the desk, delayed deadlines that must be met immediately, and 87 phone calls to return. Who can relax when the stress of playing catch-up sets in? That's your punishment for taking time off.

So what ever happened to the predicted four-day work week, when computers would allow leisure time unknown to pretechnology wage earners? We use computers. Our coworkers use computers. Our suppliers use computers. Our customers use computers. But we're all working harder than we did before computers, it seems.

It wasn't too long ago, 1955 to be exact, when C. Northcote Parkinson put in writing in The Economist a theory that we all recognized as a truism: Work expands to fill the time. You know, just like junk expands to fill attic space. Or documents expand to fill hard disk space.

We really did think computers would so enhance personal productivity as to allow us actually to leave the office by 5 p.m. and not work weekends. Let me quote the very first paragraph from the very first Computer Sense column in this magazine, March 1984: "Do you sometimes wonder where you'll get the time to finish One more job assignment after another. Would 40 extra working days over the next year help? They're yours - with the average 15 percent productivity gain you'll get by using a desktop computer." Yes, I wrote that. The statistics proved it true, but only for a short time. Computers have been a blessing and a curse.

Edward Tenner calls it the revenge effect. In theory, technology improves our world. In practice, those #%*! machines are out to get us! In "Revenge Theory," an article in Harvard Magazine, Tenner classifies the causes of technology troubles as repeating, recomplicating, recongesting, regenerating, and rearranging.

"Repeating" is the universal tendency that hits communicators between the eyes, I'm convinced. When retyping a manuscript took up too much of a secretary's time, the writer made only the essential edits. Word processing made corrections quick and easy. Now we edit not merely one or two times, but constantly until 17 seconds before deadline.

"|Recomplicating' is another ironic consequence of the simplifying abilities of computers," Tenner wrote. The VCR is a frustrating example. We were supposed to be able to shift our viewing, to watch shows at our leisure regardless of when they were broadcast. But we can't figure out how to program the thing to record shows during off-leisure hours.

In "recongesting," we clog up the frontiers opened by technology. Consider man-made debris floating in outer pace, so much so that space junk threatens space travel.

"Regenerating" involves a solution that revives or amplifies the problem. "Bacteria have a hydra-like way of multiplying in response to bathing and even surgical scrubbing, possibly because heat and moisture split large colonies into smaller ones," Tenner writes.

And finally, "rearranging," which merely shifts the problem. Tenner's example: "The 1970 U.S. Clean Air Act, by requiring high smokestacks to protect the surroundings of Midwestern coal-burning plants, ensured the windborne transport of sulfur dioxide, spreading acid rain to woodlands and waters hundreds of miles away."

The revenge effect has affected technology and bureaucracies for years. Pesticides destroy natural predators, requiring more pesticides. Better highways just made the rush-hour parking lots longer. Forest fire control allowed combustible materials to accumulate and cause bigger forest fires.

So have scholars and experts learned anything about unintended consequences, formulating strategies against revenge effects? Tenner offers two bits of practical wisdom.

First, be clear about your expectations. It isn't "wicked or foolish to print out three or four drafts of a document," Tenner says. Just recognize that you have a choice in the matter.

Second, be sure you can get along without the technology. "Those who can write fluently with pencil and paper are best able to use the computer's powers of revision," Tenner writes. "People who can work with constraint are able to get the most out of power."

Remember what happened when you put the carbon paper in backwards while typing duplicate copies on the ol' manual? Technology changes, but problems remain.