The quote from Milan Kundera's "The Unbearable Lightness of Being" suggests that human experience is linear rather than cyclical. This perspective implies that as people move forward through time, they lose the ability to revisit moments that bring joy, creating a sense of longing for the past.
Kundera indicates that happiness is tied to the ability to relive joyful experiences. Since time is continuously advancing and not repeating, individuals find it challenging to attain true happiness, as they yearn for the recurrence of fulfilling moments that can never fully come back.