I'm a luxury car body man. We do have people that do some crazy things. The worst part is they don't pay attention to their car as close until its wrecked. They will scrutinize that part of the car that was wrecked until they are blind. Then they'll complain that other parts of the car weren't like that before the accident. I happens a bunch but its part of the job. Good part now is I have to same goggles on when I look at the cars. I exactly know what to look for before it gets to the customer.
The best customer I can think of is a customer doing the ball bearing gap test. He saw it on a Lexus commercial so it has to be true.