A Case of the GPS

AITOOW wonders if it isn't just a-holes checking their Facebook updates or texts that is responsible for all the ridiculousness we encounter on the roads? Is GPS a major contributor? Are people driving without knowing (visualizing the route) where they are going? Is this why there are so many last minute lane changes. etc. Is this why cars are creeping along timidly (like they are waiting for a change in direction)? Is the fact that GPS's are often wrong a reason for suspect actions on the road?