Fuel consumption and greenhouse-gas emissions: Let's assume there'd be about 20-per-cent fewer cars on the road for morning and afternoon rush hours. That would constitute a major reduction in crude oil usage. The same percentage decline would apply to chemical compounds spewed by cars and trucks - carbon monoxide and dioxide, sulphur dioxide, nitrogen oxides, hydrocarbons, ozone, lead and chloro-fluorocarbons. Global warming might even be reduced.
Disposable income: The 20-per-cent savings on gas, car maintenance and insurance would accrue to personal pocketbooks. The family sedan would last longer. Money otherwise allocated to these budget categories could be spent consuming other goods and services - so that overall levels of demand and consumption would not be affected.
Corporate incentives: Far from seeing the four-day week as a threat to productivity, the business world should welcome it. There would be significantly less absenteeism. With less stress on employees, companies would also be able to cut budgets for workplace stress-reduction and physiotherapy programs. Their own costs for heat, lights, security and building or office maintenance would also decline.
The well-being app: And finally, the three-day weekend's Killer App - call it the Well-Being App.
There'd be more time. Time for the family, a demonstrable, arguably urgent, need. And more time for the self. You could start that cottage industry you've been planning for years. Finish the screenplay. Take your kids on long hikes.
With more time, you would be able to cook more and eat out less (additional savings). You would watch less television. The habit is actually a reflex of exhaustion - European studies show that four-day workers are less inclined to park in front of the tube.
Instead of dropping your toddler at the day-care centre, you'd have one more day a week with him or her. Instead of missing the ballet class or the hockey game because of a corporate meeting, you would be there for it, video-camera in hand.
As a practical matter, "we need not adopt a one-size-fits-all template," says John De Graaf, who runs the Seattle-based movement Take Back Your Time. "We have to recognize that people have different needs."
But in dozens of ways, large and small, the three-day weekend would begin to repair the breach that has formed at the heart of Western culture - a breach in the quality of our lives.
Perhaps we need to become like Bartleby the scrivener in Herman Melville's short story. His boss repeatedly gives him assignments, to which the inscrutable legal assistant repeatedly says, "I'd prefer not to."
If Facebook and Twitter postings can inspire a revolution that topples a dictator in Egypt, a campaign for a four-day workweek should be a piece of cake.
You have the next three days - at least - to think about it.
Michael Posner is a feature writer for the Globe and Mail.