In 1990's Leo Burnett was shortlisted to pitch Microsoft Advertising Account. As the
story goes, Bill gates visited Leo Burnett office and the creative team shared there ideas. After the pitch Mr. Gates was reportedly treated to the customary agency tour. At the end of his tour Bill Gates exclaimed, "Excellent presentation gentlemen, but as I see it,you don't use computers and that would make it impossible for you to understand my business."
Source: David Everitt-Carlson's wild wild East