The film won four Oscars in 1977: Best Actress in a Leading Role (Diane Keaton), Best Director (Woody Allen), Best Writing and Best Picture.
The original title was Anhedonia, meaning the inability to experience pleasure. Allen's character Alvy Singer suffers from the condition until he meets Annie (Keaton, whose last name at birth was Hall). With all of her fumbling and self-consciousness, Annie is a beautiful vessel of pleasure.
Alvy tells Annie that her whole body is an erogenous zone, and soon it is revealed that she insists on smoking pot before they make love. When Alvy objects, comparing it to a comic getting a laugh too easily, Annie tells him if he'd only smoke with her, he wouldn't have to see a therapist.
The following scene has Alvy picking out books on death for Annie at a bookstore, telling her he divides the world into the miserable and the horrible. Obviously, he refused to smoke, saying if he smokes or drinks, "I get unbearably wonderful."
It's Allen's most direct statement on the drug experience until Alice (1990), a retelling of Alice in Wonderland that's a lot more interesting than the one starring Johnny Depp.
Keaton also smokes pot on film (in a bathtub) in 1982's Shoot the Moon. In 2005, she appeared as the cancer-stricken matriarch of The Family Stone, in which she takes "special" medicinal brownies, and Luke Wilson helps the uptight Sarah Jessica Parker to loosen up with a bit of the holy herb.