From the book Artful Persuasion by Harry Mills:
Advertisers know that, in most advertisements, the headline is the by far the most important element. Most people read little else. It took David Ogilvy 104 drafts before he came up with the classic headline:
At 60 miles an hour the loudest noise in the new Rolls-Royce comes from the electric clockThe advertisement became a model for copywriters everywhere. Legend has it that when David offered it to Rolls-Royce for approval, the executive in charge paused, frowned and said, "We really must do something to improve the damn clock!"