Final answer:
The onset of adulthood is marked by amplified responsibility, leading to a shift in what is considered enjoyable. People embrace new social roles, leave behind youthful pleasures, and focus more on career and family commitments.
Step-by-step explanation:
The statement 'When responsibility begins to pass, fun isn't fun any longer.' reflects the onset of adulthood, a stage in life associated with increased obligations and expectations. During adulthood, individuals take on new roles and more serious commitments such as marriage, parenting, and career-focused endeavors. In this life stage, the pleasures once enjoyed during youth, like spontaneous outings and casual relationships, are often replaced by the need for stability and responsibility. As people age and enter middle adulthood, they face the task of generativity versus stagnation, where they can either contribute positively to society or face a lack of connection and productivity.