"The best lines come out of real life. You catch one, you shine a light on it and you put it in the right situation."

That encapsulates how Howie Cohen, now an exec at the Phelps agency in Los Angeles, came up with some winning campaigns during the 1960s for Wells Rich Greene while working on the Miles Laboratories account. There, his original designation as "backup to the backup" creative on the Alka-Seltzer business led to the side-splitting but relatable "Try it, you'll like it" and "I can't believe I ate the whole thing."

Mr. Cohen says the first line came from his childhood exhortations. The second came as a result of an Italian restaurant meal with Milos Forman. We'll let Mr. Cohen tell the story, but first, make sure to finish your dinner.

Video and interview by Nathan Skid