The film: Tom Hanks plays Gump, an endearing half-wit with a knack for factoring into many of the 20th century's critical moments.
The line: "My momma always said, 'Life was like a box of chocolates. You never know what you're gonna get.'"
The setup: It's said by Gump as he offers one of his rotating cast of listeners a piece of chocolate. The line is enhanced by the slow, Southern drawl Hanks adopted for the film, which led to endless (and usually poor) imitations.