On Christmas Eve, as Lucy, Ricky, Fred, and Ethel decorate the tree, they reminisce about good times from their past. This is the earliest example of a "clip show" ever produced for television. Many people in the U.S. did not have television sets when "I Love Lucy" first came on the air in 1951. Five years later, with TV sales having skyrocketed—as well as the number of "I Love Lucy" fans—this retrospective episode was created to give many people a chance to see clips from previous episodes for the first time.