When William comes over to Mary's, he pulls out a packet of cigarettes and offers one to Mary - who refuses, saying, 'I don't smoke'. In actual fact, Mary Tyler Moore was a cigarette smoker but was adamant that neither her character smoke nor would she allow pictures to be taken of her off-camera showing her smoking. She knew it was a bad habit, and did not want to be seen, in any way, encouraging people to pick them up.
Mary says she is fifteen years older than William. In reality, Mary Tyler Moore was twenty years older than Jean-Michel Michenaud.
The tune "Fascination", played at a lunch, has music written in 1905 by Fermo Dante Marchetti. English lyrics ("It was fascination, I know...") by Dick Manning. It has been recorded many times in many different languages, in 1957 in English by Dinah Shore and Jane Morgan.
The actor, J. Benjamin Chulay, who played the mail boy is uncredited here. However, he already played a background office worker in the newsroom a number of times before. He eventually was referred to as "Pete" in later episodes.
Mary tells William she cannot date him because she's 15 years older than him. Mary Tyler Moore was 15 years older than her 3rd husband, Dr. Robert Levine.