Ursula Buffay (Lisa Kudrow), the waitress, is Phoebe Buffay's (Lisa Kudrow) twin sister, from Friends (1994). In one episode of Friends (1994), Fran (Leila Kenzle) and Jamie (Helen Hunt) visit the coffee house, and mistake Phoebe for Ursula.
In one episode, Paul and Jamie see Ursula after a long time of absence in the show. They ask her where she had been, and she says "I've been hanging out with friends". Ursula is portrayed by Lisa Kudrow, who starred in Friends (1994), thus her absence in this show.
Paul and Jamie's daughter, Mabel, got her name from her grandmother (played by Carol Burnett). When Paul and Jamie were looking for a name, Jamie's mother said to them, "Mothers always bring extra love" M.A.B.E.L.
Steve Buscemi appears in an episode in the first season, which was inspired by an actual incident between Paul Reiser and him. Before Buscemi began acting, he tried his hand at doing stand-up. One night, he bombed so badly, that another comic had to take his place. That comic was Reiser, and the episode pokes fun at the incident.
Paul Reiser's production company is called Nuance Productions, after a line in the first film he appeared in, Diner (1982): "You know what word I'm not comfortable with? Nuance. It's not a real word. Like "gesture". Gesture's a real word. With gesture you know where you stand. But nuance? I don't know. Maybe I'm wrong."
Some episodes are appropriate for all viewers to watch, while others have more adult content than the others. Three viewers discretional ratings were used, which were TV-G, TV-PG, and TV-14. No episode had a viewers rating of TV-MA.
The sixth season episode, "The Conversation", has the entire episode and the credits scene both shot in a single take after two rehearsals. Because of the episode taking place by a bedroom door, the episode was never popular with audiences despite the intimate scale and approach.
The trivia item below may give away important plot points.
In one episode, a character asks if they saw the movie about those aliens that burst from people's chests (the Alien movies), and Paul Reiser says, "Only the first one." Reiser starred (and gets killed) in Aliens (1986).