I too lead a very charmed life.
The only thing I've ever had go wrong happened in January in Hawaii. I had driven from the west side of Honolulu to all over kingdom come trying to find this blasted Thai restuarant on the east side of the island. I was absolutely famished by the time I found it, two hours later. Naturally, it was closed by the time I got there. Ack! I got back in the car, resigned myself to the Taco Bell across the street and parked. The key WOULD NOT come out of the blasted ignition. I tried for ages to work it out -- no go. Obviously, my only option was to drive an hour back to Honolulu Airport to exchange it. The Hertz folks couldn't get the key out either and asked what I did to it!!!! What a buzzkill on an otherwise lovely day.
But that's it. In all my travels, much of it by myself in countries where I don't speak but tens words of the local langauge, I've never had a problem. When I was in Berlin heading back to Prague by train, the conductor barely glanced through my (U.S.) passport before tossing it back at me, but really roughed up a woman sitting a few seats away who had a Romanian passport. They physically removed her from the train and not in a very gentle manner. I was a little shaken by it, actually. Was she a criminal, or just unlucky enough to have been born in the wrong country at the wrong time? I thank my lucky stars, and often.
Samantha