I get really grinchy right up until Christmas morning.

Aykroyd’s line uses the pop-cultural shorthand of the Grinch—irritable, anti-festive, resistant to holiday cheer—to describe a mood many people recognize: the stress and impatience that can build in the run-up to Christmas. The phrase “right up until Christmas morning” suggests a sudden emotional pivot once the day arrives, implying that the anticipation, obligations, and logistics of the season (shopping, travel, social expectations) are what provoke the “grinchy” feeling, not the holiday itself. The humor lies in the candid admission and the self-deprecating framing, aligning personal temperament with a well-known seasonal archetype.