Most of us have heard the slogan chanted by Donald Trump and his supporters, "Make America great again," that refers to the utopian period of the Reagan presidency. Each of us, individually, has varying opinions of how "great" the Reagan period really was, but this highlights a different habit of Americans, and of human beings in general: looking towards the fonder days of the past to help us disparage and downplay the present.
Beset by our current issues today, it's easy for us to look to a time when things seemed better, or at least normal. While bombarded by final exams and papers towards the end of a college semester, we may look towards how much better it seemed last semester or the semester before. In reality, the feeling was the same: we were as overwhelmed then as we were now. In being overwhelmed, we have a tendency to look for comfort to times when things seemed better, and that's normal because that tendency can be used as a coping mechanism to push through a temporarily difficult situation.
But after the immediate satisfaction of finally being done with that arduous task, whether it was sitting through a horrendously long plane ride or taking an exam that fried your brain worse than the SAT, many of our brains focus on tasks and problems in our near futures and we dread the hardships we face. Immediately, we become nostalgic of "the good old days" yet again, even though in those days we suffered similar stress and uncertainty.
That is not to say that nothing has changed from "the good old days" to the present: change in life is a dynamic tug of war. While you may have had more friends you interact with daily five years ago, you could have more close friends now that you spend more time with.
The tendency to only focus on what we feel has regressed, and ignore the progress we've made since is a mark of hindsight bias -- the psychological tendency to view events in the past as more predictable than they are in the present. It's the underlying reason for the nostalgia we have thinking of "the good old days," looking with a mostly fatalistic outlook at the uncertainty of what's ahead. In difficult times, this tendency is a desire to return to when things were seemed better, or at least seemed normal.
The hindsight bias of "the good old days" is a psychological fallacy we have internally and socially constructed to avoid the reality of the daunting present and future. It parallels the idyllic lives of Adam and Eve in the Garden of Eden before the fall of man. It's highly unlikely that we've experienced life like that, and even more importantly, "the good old days" aren't going to help us with our problems, now.