When Sam, Diane, and Frasier are in Sam's office and Diane tells Frasier to look in Sam's eyes, the shadow of the camera is visible as Frasier walks over to Sam.
In the first scene after the credits when Diane orders a vodka rocks, the shadow of the boom mic is visible on the rear wall.
Diane makes an uncharacteristic grammatical error when she says the relationship "between Sam and I" is over. It should be. "...Sam and me..."