There are two things in this life for which we are never fully prepared: twins.

Cast as a mock “life lesson,” the line uses the sudden punch of the final word—“twins”—to deflate the expectation that a profound second item will follow “two things.” The humor rests on a common parental anxiety: even careful planning cannot fully anticipate the demands of raising children, and twins multiply the unpredictability at once. In Josh Billings’s folksy, aphoristic style, the quip also satirizes the human desire to feel prepared and in control; some experiences arrive as a surprise regardless of forethought. The joke’s brevity and misdirection make it memorable and easily repeatable as a wry comment on parenthood and life’s unplannable turns.