First Date - S5-E20
Continuity mistake: Frasier and Niles are in the kitchen while Daphne is getting some fabric softener - Niles is holding a blue bottle of water up near his chest but in the next shot it is down by his waist.
First Date - S5-E20
Continuity mistake: While they are in the living room, Niles is telling Frasier about Phyllis, and he has his bottle of water in his left hand but as the shot changes and Frasier says "Oh, good lord", the bottle switches to Niles' right 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 ★