The Dvorak Blog has a nice piece (by Uncle Dave) on the technology that pacifies us by giving us the Illusion of control. The piece mentions 'close' buttons in elevators that usually do nothing; 'Walk buttons' for pedestrians at traffic lights (in Manhattan, apparently it is known that many of them intentionally do nothing); and thermostats placed in offices in commercial buildings that are connected to nothing. (The illusive thermostats prevent people from calling the heating company to complain about the temperature.)
Someone commenting on this piece mentioned the buttons in electronic voting booths, suggesting that no matter which buttons you press, nothing seems to happen.
I would like to take issue with the elevator 'close' button. It is true that if you press 'close' the moment the elevator doors open, your pressage usually has no effect. And I know we are all tempted to do that when the doors open at some floor where no one seems to be waiting. But try this: wait a little more than a second after the doors open, and then press close. Often, the doors will respond at once.