The first of seven appearances of Cliff's mother, played by Frances Sternhagen. The character had been mentioned many times prior to this episode.
The opening scene revolves around Cliff returning from "Expo". Expo 86 (1986 World Exposition on Transportation and Communication) was a World's Fair which was held in Vancouver, BC, Canada. It ran from May 2 through October 13. 54 countries participated. It was the last BIE sanctioned World's Fair to be held in the Americas.
Sam is seen telling a punchline to a joke. The entire joke: A man who had just bought a live chicken and then impulsively goes to a movie theater, hiding the chicken in his pants so the ticket-taker won't hassle him about bringing a bird into the theater. Once in his seat, sitting next to two women, he opens his fly so the chicken can stick out its head and breathe easily. In the darkened theater, the women misinterpret what the man is doing. The first woman says to her friend, 'This man's fly is open!' The second woman says, 'When you've seen one, you've seen them all!' The first woman says, 'Yeah, but this one's eating my popcorn!'"
Ma Clavin appears to not know anyone in cheers, but in a previous season Norm had gone to Cliff's house for a painting party and Cliff's mother was there arguing with Cliff.