Insomnia is a frequent challenge for me, so I was interested when a friend told me about one of those herbal teas that is supposed to help one relax and fall asleep more easily. Hoping for the best, I drank a cup a little before bedtime—only to be awakened some time later with an extremely full bladder, more so than should have resulted from a small cup of tea near bedtime.

I decided to do a little checking on the ingredients. As expected, I found herbs known to promote relaxation and sleep. Then I found something I definitely wouldn’t have expected. One of the ingredients was a diuretic. Sleep promoter and diuretic: not a good combination!

Did the people who created this herb tea never try drinking it themselves? No, I’m sure they did—but probably during the day time, and probably only in small spoonfuls. In other words, they tested their design for a new herb tea in unrealistic circumstances, circumstances which did not reflect the users’ reality. In doing so, they missed a major problem—a deal breaker, in fact. (I never bought that tea again!)

A design may look good on paper or on the screen. Without trying it in a realistic scenario, users may even tell you it would work. But you never know a design really works until you’ve proven it in the crucible of realistic experience.