The GPS is a marvelous tool all right, but you still have to be smarter than it. I usually check a map prior to a trip so I know where it is I am going. Then if a turn looks suspicious, I don't take it. Course the GPS is most always correct.
Garmin has a program you can download for free that lets you record any voice to the commands you want. They download a program and script that you follow and then upload into your Garmin.
My plan, was soon as I can slow them down long enough, is to have my Grandchildren read the script. You can modify commands as you see fit. Imagine instead of "Recalculating" your Grandchild will exclaim, "Grandpa, you missed your turn again".
Retired FAA ATC, VFW, LEGION, NRA (Life Member)
2002 Journey D L 36, 2013 Demco KarKaddy III,
Toad 2012 VW Passat Diesel
Lost little Bitzy
New kitty named Oreo.