Ross Hunter wrote that after he made this film, no theatre managers wanted to book it. Popular movie themes at the time were war films, westerns, and spectacles. Hunter was told by the big movie chains that sophisticated comedies like this movie went out with William Powell. They also believed that Doris Day and Rock Hudson were things of the past and had been overtaken by newer stars. Hunter persuaded Sol Schwartz, who owned the Palace Theatre in New York, to book the film for a two-week run, and it was a smash hit. The public had been starved for romantic comedy, and theatre owners who had previously turned down Hunter now had to deal with him on HIS terms.

After Jonathan (Tony Randall) slaps Jan (Doris Day) in the diner, a truck driver (John Indrisano) punches him in the jaw. In an interview, Randall said that he and Indrisano practiced the punch many times, and Indrisano assured him that he would not be hit. During the take, Indrisano misjudged, and Randall actually was struck and knocked unconscious.

This movie would be the first of three to showcase the trio of Doris Day, Rock Hudson, and Tony Randall. It was followed by Lover Come Back (1961) and Send Me No Flowers (1964), with all three actors portraying different roles in each.

Despite being contractually bound by Universal to do the film, Rock Hudson consistently declined it, fearing it was too dirty and would harm his masculine image. Doris Day finally talked him into starring in it, and it subsequently became one of his biggest hits.

Rock Hudson turned down the film three times, believing the script to be "too risqu?"".

Continuity

When Jan and Jonathan are talking in front of the interior design store about the car he is offering her, the same extras are seen multiple times. A woman with a blue coat and gray hat walks by four times, and a woman with a red coat walks by at least three times.

Brad's watch disappears as he holds his coffee cup.

When Jan is looking at Brad's apartment before she redecorates it, Brad knocks a red pillow off the couch as he jumps up when Jan is investigating the switches behind the couch. When she flips the second switch revealing the hide-a-bed, all of the red pillows are back on the couch.

When Jonathan (Tony Randall) gets hit in the diner, he gets hit on the right side of his jaw (the man swings with his left arm), yet in his office in the next scene he has a bruise on the left side of his jaw.



Factual errors

A party line phone would not ring if any phone on the line was off the hook. To call another phone on the same line, a special code was dialed, then the phone was hung up which would cause the originating phone to start ringing. When the phone stopped ringing, the caller would know that the other party had answered. This is not how Brad does it.

A party line combines the phone lines for customers that are physically near each other, such as adjacent apartments or houses next to each other. For Brad to carry Jan from one building to another, each having hundreds of apartments, and with both of their apartments on the same party line, this is impossible.



Incorrectly regarded as goofs

When confronting Brad in the nightclub, Jonathan mockingly calls Brad "Tex" instead of his correct alias, "Rex." Jonathan is using "Tex" as a generic nickname for a Texan; he is not trying to use Brad's alias.



Audio/visual unsynchronized

When Jan and "Rex" are at the piano bar singing 'Roly Poly', the man behind the pianist is strumming a four-string electric bass guitar, but the sound is from a six-string electric guitar.

When Brad sees his redecorated apartment, the cat continues to meow even though its mouth is closed.



Crew or equipment visible

When Brad is carrying Jan out of her apartment, the board on which she is supported can be seen.



Character error

When at the bar singing 'Roly Poly' with Jan, "Rex" lets his real accent slip a few times.