Standing in line: how long is too long?

I knew Americans' patience was thin, but now we know how thin: four minutes' worth.

According to a story that just came out in the supermarket trade publication, Progressive Grocer, a research firm has just released new shopping data demonstrating hat 10 percent of shoppers get exasperated enough to leave a checkout line if the wait is lengthy. They polled 13,000 consumers to determine exactly when the breaking point is for most shoppers, and it appears to be four minutes. People are happy if they wait under four minutes; over four minutes, and their blood pressure starts rising.

The only exception seems to be at club stores, where an average wait time of over slightly four minutes is still considered acceptable. But after four minutes, whether you're at a grocery store, consumer electronics, department store, drug, home improvement, mass merchandisers or office supply store, it's all the same -- people get annoyed.