I tell the students that this is also what I do when making their lectures. I can't cover everything. I must trim my list down to a manageable amount of content.
This means that, like our example, sometimes a decade may seem really bleak, because the big stuff we cover is dark. But just like their experience in the last 20 years, people continued living their lives and enjoying themselves despite sometimes dark moments.
Finally, I ask students if they think their lists will look any different if they made them again 20 years from now. I ask if they think my lectures over more recent history like the Obama administration have changed any since he left office.
After some discussion, I conclude with the point that our perspective about what matters can change over time, even when the facts don't change. The Apprentice television show wouldn't be remembered in history books, except for the fact that its host went on to be president. Barack Obama's Vice President may have been a footnote, except for the fact that he too went on to be president. The future changes how we see the past.
If you'd like access to my slides (pictured above), use the link below for a shareable version.