Cinematically Cinched...at the Waist

Irene Dunne
The Awful Truth, 1937
Gowns by Kalloch
The quintessential screwball comedy with the quintessential leading man (see also the perfect romantic comedy).
I could go on and on about how they don't make 'em like this anymore--A-list cast, director and script, stunning gowns, pitch perfect comedic timing, etc, etc--but you should see it for yourself then marvel at the fact that no one is really witty or clever anymore.