So screams the repressed Alison (Daphne Zuniga) in Rob Reiner’s The Sure Thing (1985). She has been pushed to this point by the more free-spirited Gib (John Cusack), who pesters her about how unspontaneous she is, especially when someone moons them on the highway and Alison is visibly disgusted by it. Gib starts jibing her, needling her, “Haven’t you ever been spontaneous?” until finally, she rips her shirt off, flings her naked torso out the window, and screams at the vehicle full of mooners: “COME TO MAMA, BOYYYYYYS.”
It’s funny because of the contrast, of course, with her uptight turtleneck-wearing overachieving personality. It’s funny also because of what she yells. She doesn’t just display her breasts, she screams this blowsy floozy come-on appropriate to a Mae West movie. So all of that is funny. But why it’s REALLY funny is what Daphne Zuniga does with her mouth and her eyes at the climax of that moment. She’s shouting at the other truck, it’s funny and all that, but then during the long drawn-out “boyyyyys”, her eyes suddenly ratchet up to an alarming level of crazy, and her mouth goes almost completely square. Even in the character’s most angry moments in the rest of the film, she never makes THAT face again. I would expect that Alison has never made that face before in her life. And neither has Daphne Zuniga in the rest of her career.
It probably shocks her as much as it does the guys in that other truck. Alison’s inner monologue: I was unaware before now that my face could actually DO that.