Frasier reveals he has a cat allergy in this episode but in the Season 11 episode "The Placeholder" he cat-sits a friend's cat named Mr. Bottomsley, thus debunking his alleged cat allergy.
Niles claims he is just now learning to cook after having left Maris. Numerous episodes before and after this one present Niles as an accomplished cook. Response: He is likely claiming to be a bad cook as a way to spend time with Daphne.
When Frasier picks up the cat carrier, they way he easily lifts it demonstrates it is actually empty.
In this episode Frasier (Kelsey Grammer) says that Paris, France is his favourite city; but in season 11's A Man, a Plan and a Gal: Julia (2003), he says that his favourite city is Florence, Italy.
Niles is incorrect that it is erroneous to end a sentence with a preposition.