I've been through the desert with a GPS called Sally

Garrison Keillor (about whom more later) does a great send-up of these devices. It takes him on unwanted detours, argues with him and willfully misinterprets his instructions, but is infinitely patient and forgiving, faithfully taking him (eventually) to his stated destination. We've named ours Sally, and I never want to be without her again when I'm driving. We tell her where we're going and she gives step-by-step instructions to turn left or right on to this that or the other road, anticipating lane-shifts and monitoring traffic flows, giving progress reports and even devising routes that involve as few left turns (think about it) as possible. Amazing. When I divert off her chosen route (as is my habit in life) she pauses just long enough for effect, then says 'Recalculating' with a weary sigh. She tirelessly recalculates, devising ingenious ways to get me back on track whilst giving the impression that my mistaken turnoff was, after all, the best route to our destination. A true friend.