The correct answer to this open question is the following.
Older adults differ from younger adults when talking about negative self-defining memories in that the older adult has lived so many more things than the younger ones, and probably has lived complex or dangerous moments that really put its life at risk or lived more traumatic events that the younger adult has not lived yet or will not live. For instance, the trauma of war. Hew generations do not have a clue about the horrors of war and what the country lived during World War I and II. And definitely, people in America did not live the fear of being bombarded, such as the people of Western Europe or Germany did for so many years. So nobody understands an event or experience until he/she lives it.