When Niles and Frasier are at the piano working on Frasier's jingle, Niles asks, "Are you sure you want to modulate here?" but the staff paper he points to is clearly blank.
The viola player asks Frasier if she's looking at 8th notes on her musical score. She should be able to figure this out easily by simply counting the number of notes in each measure.
When Frasier is addressing the viola player he describes the "yearning of the super ego". As a psychiatrist he should know that the super ego does not yearn, the id yearns. The super ego judges and controls.