Well, it's not 'directing' you anywhere. If you're driving on a real road and the GPS shows a blank screen, it's an indication that the GPS's map database is entirely inadequate to the situation.

This keeps my skepticism intact regarding the real value of GPS.

Time to break out the maps.

[Edit: whoops, several posts beat me to it. I can certainly see the value of waypoints and breadcrumbs, but if I have to carry map and compass anyway, I'm not quite clear how I'm ahead.]