Watch a Classic Harvey Pekar Moment on David Letterman
The legendary and recently deceased comic-book author made a notorious appearance on Letterman in 1988, during which he ranted against NBC's corporate owner General Electric. He later said of it: "[W]ith Letterman ... you either lay down and let him insult you or you do something about it. Most people keep their mouth shut and let him dump on them. I don't wanna do that." Which makes for awesomely awkward TV.