The problem I have with so many GPS nav systems is the lack of sensible assumptions (I suspect because someone has a patent on them and wants too much for royalties). For example when you go off route why not pop up a screen that asks if you want a local detour or ignore routing for a couple of minutes so you can fuel up, maybe go so far as to give 4 options, route for local detour that can then be upgraded to major detour, route for services (food, lodging, fuel,etc.), suspend routing, or get me back on route, with get me back on route being the default if no choice is made in a timely manner. Instead of this we get to hear "make a U turn when possible", over and over. For that matter maybe take the hint when we fail to make that U turn 4 or 5 times in a row.
While we are at it how about a few more routing options, generally it seems we get avoid toll roads, avoid ferries and a couple of others. How about avoid congested area / avoid large cities, avoid substandard roads, avoid construction zones, etc.