I love my Evo tablet—it has revolutionized the way I manage my life. Like most tablet owners, I try to maximize battery life. One of the main ways I do so is by keeping the screen on its dimmest setting when I’m indoors.

But my tablet has an odd quirk: when it alerts me that the battery level has reached critical, it simultaneously adjusts the screen brightness to the highest setting! At the very point when my tablet most needs to conserve battery power, the tablet changes my setting to drain the battery even more quickly.

Was this intentional? I doubt it. I can’t imagine a developer coding a battery alert to include a power drain. So it was probably caused by a unexpected line of code somewhere. But once again, it points to the importance of testing designs in realistic scenarios to make sure they work as expected and are free of glitches. User testing adds to the cost of the project; but failing to do user testing costs even more.