Back in the 80's Chevrolet made some training videos for dealers. And it would be hard to believe that these actually helped to sell cars.
http://www.autoblog.com/2009/08/21/video-chevy-dealer-training-film-from-the-eighties-makes-you-wo/
http://www.autoblog.com/2009/08/21/video-chevy-dealer-training-film-from-the-eighties-makes-you-wo/