The thing to remember is that the typical consumer GPS actually has several components.
First there is the actual GPS itself, which uses satellites to provide an XYZ location. In most cases, this location is accurate to within a few meters. Then there is the location database. This is a compilation of highways, roads, and streets. It also has info about whether the road is two way or one way (with direction), how many lanes, etc. These databases are compiled from a huge variety of sources, and are not always up to date. Finally there is software that connects the GPS to the database.
I think most of the problems come from the database, rather than the GPS itself. As noted, these databases contain info on millions of highways, roads, streets, etc. Even if the data were perfect to begin with (which is never the case), it is constantly changing. New roads are built, streets are blocked off, re-named, or re-routed. No position database is ever likely to be fully up to date.
Also note that you can get into serious trouble following a paper map. The well known
Kim tragedy was a result of trying to follow a paper highway map. Paper maps are not always accurate or up to date.
The best way to avoid these situations (whether from GPS or printed maps) is to use common sense. If a road is supposed to be taking you to a more "civilized" place, but the road is getting worse instead of better, maybe that is a sign that you need to stop and re-evaluate?