A few years back I was driving to my brother's home, about 400 miles away, and set the GPS for "Shortest Route." During the course of the trip the thing kept trying me to make a left turn, including ones that would have taken me down country roads and jeep tracks. Finally, as I got within about 20 miles of my brother's house and was approaching a really irritating intersection with a history of delays, I turned left as instructed, figuring the results could hardly be any worse. After a few turns left and right I was astonished to see a radar antenna, spinning away, appear nearby on my right.
My reaction: "Holy crap! I did not know this crazy thing had a Wild Weasel mode!"
On another occasion a few years later my brother and I were returning to his home from a very rural address where I had picked up a part for my airplane. There was no suitable easy direct route and following the main roads would have required we transit a notorious area nicknamed "malfunction junction" which, as an extra attraction, was undergoing extensive maintenance and modification. So I decided to let GPS find us a more direct and less heavily traveled route. At one point we turned down a road the GPS had designated and noted a Dead End sign displayed. I figured that, notwithstanding the sign, the GPS said we could get through there. We came to the dead end and found it enabled access to a power line maintenance road that ran under the high tension lines; I decided not to take that route given that we were in a Toyota Matrix, but if I had been in my 4X4 Tacoma I might have tried it.