I saw this when I was 10, when movies were double features and the fare changed weekly. I only remembered it because I loved Day, not because of being an actress, but because she was Leo Durocher's wife and I was a Baseball nut. I saw it again recently on TCM. This movie defies a reason for being, except that the studios needed constant fodder and this film proves the point that it was often volume over content. We are still being crammed with movies that ask the same question, What Were They Thinking, but lack the old excuse.
Day's acting, consisting primarily from 'reacting', is an embarrassment on the same footing as the unlikely dialogue given to the rest of the cast. Her opening scene with Clark makes for great comedy as she goes thru a 360 degree range of reactions to his 25 or so separate avenues of dialogue, mostly questions she never answers. And he's oblivious to the strangeness of her conduct. From there it only gets worse.
It's hard to believe it's the same Day who shown so brilliantly in Mr. Lucky or a movie with such confusing plot turns, but unlike The Big Sleep, where you didn't notice or care.