Throughout the Season 3 Season Premiere, the events take place on and around December 31. The characters continually refer to events as "Holiday Luncheon" and repeat "Happy Holidays". This appears to be a modern day conceit of HBO. No one in the 1920s would have referred to the season as "the holiday season" rather they would have used terms such as "Christmas luncheon, Christmas party or Christmas Season." They most certainly would have wished each other "Merry Christmas" rather than "Happy Holidays". In many instances, give the influx of immigrants from the United Kingdom, the proper term would have actually "Happy Christmas". Similarly, a doctor talks to Margaret Thompson about raw milk and E.coli. A look into the history of 1922-24 reveals that E.coli was not a widely known term or widely publicized issue. Most certainly a doctor would not discuss this with Margaret Thompson, then known as a philanthropist as she and Nucky had a hospital wing named for them due to their donations.