99-00 or so I was working for Enterprise Rent A Car in San Diego. Our branch was in a Land Rover/Porche dealership. Lady comes in to Land Rover one day and complains that her Range Rover is slow, getting terrible gas mileage, and loud.
Being a hot trophy wife all 4 service writers are eager to help her.
Service writers go out and look at it.
Come back in 3 minutes later slapping themselves on the back and laughing hysterically.
She'd been driving it around daily for several weeks in 4lo. Luckily the Rover's central diff was slipping enough to not just blow stuff up.