Continuity mistake: Frasier is handed a beer with an inch or two of froth. When the shot changes the froth has all but disappeared. (00:15:30)
Continuity mistake: During the opening credits, Niles, Roz, and Daphne are sitting on the couch. Niles has put Frasier's biography on the coffee table but when the shot changes and Frasier comes in, Niles is suddenly holding the bio in his hand.
Answer: Nanny G (Nanette Guzman - played by Laurie Metcaf) has been a children's entertainer for twenty years, and tells Frasier, "Do you know what it's like to play the same character for 20 years?!" The joke is that Kelsey Grammer has been playing Frasier Crane since 1984, when the character first appeared on "Cheers", so Kelsey in real life has been doing just that!
Super Grover ★