Only once has GPS directions on my smart phone been perfect. Just 3 days ago my Wife went on a 148 mile trip to visit a friend in the Hospital. The app sent her 10 miles in the wrong direction, but got her 95% of the way there. I don’t trust them and never have.
Yes, phone GPS is certainly less than perfect. I have been misled by it as well.
But with my lack of good directional sense, it has certainly saved me a lot of hassles too.