Another funny issue is when the amatuer/beginner is arguing with a seasoned pro about something, without proof, then calls the pro an idiot because he tried correcting the beginner. I had a Pentax K1000 user with a Promaster lens telling me that "old, cheap" cameras like mine are useless and that "I should upgrade to something more modern". Hmm. So, my Hasselblad is obviously worse than his K1000.
I told the guy that my camera wasn't that old, then I noticed they black electrical tape which was wound tightly around his Vivitar something flash. (Walmart special). Yes, it was even wound around the light-shutoff sensor for the auto-thyristor. I later noticed the guy shooting around the corner (he was doing some sort of "model" shoot) with his flash firing off at full power.
I told they guy about they sensor and (in laymen's terms) how it worked and why it needed to be uncovered. They guy proceeded to lecture me about he is also an "electronics hobbyist" and that "I am definitely wrong". Hmm, I decided not to tell the guy that I'd been an electronics engineer for about 10 years now and I just walked off.
Saw the guy two weeks later, and the tape was off the flash. He ran the opposite direction when he saw me coming towards him. I hate people who are afraid to acknowledge their mistakes!