Most likely the GPS is right, but they can lose signal, freeze up or have the incorrect route put in! However your GPS is unlikely to continue functioning, updating your position, heading and speed, and show you in the wrong position! Most unlikely indeed!
Unless it is the one in the Ipad2
Somehow that manages to do stuff I have never seen on a GPS before. Or maybe that is just the app (Memory Map).
I just feel like im cheating on the way i was taught
If you really feel that way, I suggest a cure would be to attend one of the utterly gripping lectures put up by the Royal Institute of Navigation
However to get in you will need to dress up like this
(I could not find a pic properly showing the obligatory sock full of sand which you stuff down the front of your trousers)