Where's the joystick?

I was in an acquisition office overseeing the acquisition of a system for signal analysts. You analyze a signal by determining the high points and the low points of the wave on a computer screen. During the predeployment testing of the system, while it was still in the developer's facility, a user from the field took one look at the system and said, "Where's the joystick?"

The universal response was, "What joystick?"

The user then told everyone that the signal analysts had a joystick on the current system that allowed them to move the cursor around the screen to the points of the signal. The developers told him that there was no joystick in the requirements document that the user helped to write, just a requirement saying, "The system will allow the user to graphically mark the points of the signal." The developers then showed him how he could use the arrow keys to move around the cursor, albeit one cursor block at a time, around the screen -- naturally a process that took 10 times as long as it would have with the joystick.

When presented with real-world information on how users currently interacted with the system, the developers naturally chose to throw the facts out -- telling the user that they didn't want to specify a joystick in case the developers found something better and faster (eg. thumbwheels). Meanwhile, here are the arrow keys...