Emergency-alert buttons should be unpressable!
Recently, poor UI design led to a false incoming-missile alert in Hawaii. This is a terrifying accident - and a failure not of the user, but of design. According to reports, the alert was in the same drop-down menu as test alerts used regularly for various internal purposes; the addition of an "Are you sure?" dialog box didn't help, since most people cruise through dozens of those every day. Buttons with serious consequences really should be unpressable - it should take unusual thought or action to press them. These kinds of designs already exist at all levels; examples from severe to mundane include the classic "turn two keys at once" to launch a missile, "break glass" to pull a fire alarm, the recessed "panic" button on your car keys, even the slightly-longer press required to engage caps lock on a Mac. I hear the employee who pressed the button has been reassigned - but the designer of this button is truly at fault.