According to Osho, the mind mistrusts joy and clings to misery because misery makes it the master. Yes, all mental states are transient, yet the joy that appears is a reflection of the eternal. Don’t let 'buts and howevers' steal it; even a moment of true joy reveals the deathless and carries you beyond mind, and seeing its transience frees you.
Joy may come and go, but it points to something timeless inside you—so don’t overthink it; feel it and let it lead you beyond your worrying mind.