At least three people called David Letterman "an asshole" on this show. Cher was the first: Late Night with David Letterman: Episode dated 22 May 1986 (1986). Shirley MacLaine was the second: Late Night with David Letterman: Episode dated 4 October 1988 (1988). Calvert DeForest, aka Larry 'Bud' Melman, was the third in August 1989.
Larry "Bud" Melman:
Good evening. Certain NBC executives feel it would be a little unkind to present this show without just a word of friendly warning. We're about to unfold a show featuring David Letterman, a man of science who sought to create a show after his own ...