Lately I recognized a usability limitation in the control interface of an elevator that I use often. The elevator doors tend to close very slow. Naturally people want to make the process faster and press the button in the elevator interface that closes the doors. However, the button to call the service is placed between the buttons to "close door" and to "open door" (sketch below). All three buttons are very close together. As I went to work this morning still feeling sleepy, I nearly pressed the service button. Fortunately recognized the mistake in time. I wonder how often the service is accidentally called at one day.