Smooth Talk (1985)

Based on a short story by Joyce Carol Oates called "Where Are You Going, Where Have You Been?", "Smooth Talk" stars Laura Dern as a bored and restless adolescent who thinks she's more in control of her sexual allure, and more capable of handling the attention she receives for it, than she is. In a deeply unsettling and slightly surreal scene, a hunky stranger (Treat Williams) comes calling for her, and she realizes that she's not as mature as she thinks. The film captures the same other-worldly quality of the short story (the scene with Treat Williams plays out almost like a feverish dream), while ably adapting it to the very different needs of a feature length film.
Dern gives a wonderful performance, one of many given by this underrated actress.