Doc Searls asked what could be more obvious to use than an elevator, to which I am about to reply. A tap. There is a new Beach Volleyball complex in Brisbane called, The Beach. There is a water bubbler there that confuses every person I have seen use it.
It’s a conventional design with a single button that would seem to produce the water from the faucet when pressed. Seem being the operative word, pressing the button does nothing but make the presser look at the button, look at the sink and look confused. Following this the person usually stands up releasing the button and shrug their shoulders only to look down at the water flowing. The problem is the tap works on the release of the button rather than the pressing of the button. It then flows for a certain amount of time and cuts off, requiring another press and release to start the water again.
It baffles, but doesn’t really surprise me how any engineer would let this design go to the factory. It is a testament to how blind we can be when designing interfaces. The engineer works with the interface as it evolves, and can easily let it evolve into a monster.