Even as an adult I find it difficult to sleep on Christmas Eve. Yuletide excitement is a potent caffeine, no matter your age.

The quote observes that Christmas anticipation is not merely a childish feeling but a durable, almost physiological excitement that can override adult composure and routine. By calling “Yuletide excitement” a “potent caffeine,” Guillemets uses a playful metaphor to translate emotion into bodily effect: the holiday functions like a stimulant, keeping the speaker awake regardless of age. The line also hints at the power of cultural rituals to reactivate memory and wonder—Christmas Eve becomes a time when adults briefly return to the heightened expectancy of childhood. Its significance lies in validating adult sentimentality without embarrassment, presenting it as natural and even energizing.