The phrase "As merry as the day is long" suggests a state of happiness or cheerfulness that is as enduring as daylight itself. In Shakespeare's "Hamlet," this expression encapsulates the hope for unending joy and contentment. It emphasizes the importance of joy in contrast to the darker themes that permeate the play, such as grief and betrayal. The line indicates that one can find solace or cheer, which is a fleeting yet vital aspect of life.

Overall, this quote reflects a desire for happiness that persists throughout the cycles of day and night. In the context of "Hamlet," it serves as a reminder that light-heartedness is crucial, especially in times marked by strife and sorrow. This duality of joy and despair mirrors the complexities of human experience portrayed in the play, highlighting an essential pursuit of happiness amid chaos.