Harriet Lichmann is Marie's bridge partner, as well as Frank's fantasy lover.
Frank uses Harriet's name on several occasions simply to goad Marie during certain arguments. This strategy proves quite effective. Frank playfully rhapsodises his delight in his make-believe romance, with even the briefest of utterances, such as "Aah Harriet", sending Marie into a rage. On one occasion, a younger, former work colleague of Frank's, 'Sam Gilula' pays a surprise visit to Frank and Marie's house: "The Mentor" - Season 8, Episode 22. Frank's unusually warm behaviour toward Sam prompts Marie to question if Sam was the lovechild of Harriet and Frank.
Although Harriet was mentioned numerous times throughout the series, she was only seen in one episode: Season 7 Episode 20 "Who's Next?".