The scene itself is also surprisingly steamy for classic-era Hollywood, with those skimpy costumes and all that crashing metaphorical surf.
Why is it so groundbreaking? Each love scene escalates further into ridiculousness to the point where the climax of the film occurs when Anastasia freaks out after Christian spanks her too hard.
In general, most audiences are down for some kind of romantic interlude in a movie just to break the tension.
The sex scene No sex here, just a tricky situation: Colbert and Gable are forced to spend the night together in a hotel room pretending to be husband and wife when their bus breaks down.
Sure, the scene was in the script, but the addition of butter was a last-minute idea suggested by Brando to director Bernardo Bertolucci, who thought it was a nice touch to add to the character's degradation.
The psychological warfare and emotional brutality from that point on is all one bundle of flesh and philosophy.
Just in case that line of dialogue up there—which is a direct quote of the pillow talk from this movie—wasn't a strong enough indicator of how awful Gigli is, here's another piece of info to solidify that framework: Martin Brest, the director, never made another film after Gigli.
Impressively, though, Secretary does double duty: It celebrates the occasionally violent intimacy between two partners while somehow launching the career of a fully empowered female actor, Gyllenhaal, who's never less than confident.