They may be doctors, scientists, CEOs, whatever but they don't have more qualifications than I do in the only subject that matters - determining if the aircraft is safe to fly. I do. And yes, sometimes they are silly, sometimes nice.
I usually make the point that I have no particular reason to get to their destination and am under no pressure to do so. (Not exactly true but close enough), So I'm only going to go if it is safe to do so. I do tell them that I've been at it for 30 years, and that if I feel comfortable taking the aircraft, they can feel comfortable also.
Seems to work so far.