Once flew an evidently nervous pax front seat in a light twin. As I started up and taxied out I noticed he was watching everything I was doing very attentively and asked a lot of questions about what random knobs and buttons were for, almost as if he was testing me.
When we got to the holding point, I carried out the pre-take off checks, then pulled out the checklist to make sure I hadn't missed one. At this he looked absolutely horrified, grabbed me by the shoulder and loudly asked "ARE YOU SURE YOU KNOW HOW TO FLY THIS THING?".
I assured him that I did, and explained why we used checklists. He then calmed down a bit, and seemed to enjoy the flight until we started the descent to the destination. As the approach was visual, I pulled out a VFR map to check some of the reporting points. At this, he again became very agitated and said "I THOUGHT YOU SAID YOU KNEW THE WAY!"
He was a bit calmer on the way back luckily.