1920 is a hundred years apart from 2020, yet how people think is largely unchanged. Human behaviour is still hinged on greed, fear, opportunity, scarcity, and basic instincts.
We have no idea what will happen in the future, but we do have a good idea about how human beings might behave in certain situations.

1920 and 2020

History shows us that people avoid pain and exertion, would lie to avoid a painful situation and would create hacks or shortcuts to skip through pain, often leading to worse problems at a later stage.
Example: A simple toothache would make people eat a painkiller tablet, which leads to many serious complications of body organs like the liver.

Avoidance Of Pain

“History never repeats itself, but man always does.”

Pain is a short-term loss, but may have some long-term gain.
Exercising can be painful or tedious for some and has great benefits if done regularly. Telling the truth can be painful, but is often the right thing to do.

Pain Is Short-Term

Small risks can sometimes combine, compound and mutate into something big. Yet the attention is always on the big stuff, and the small stuff happening around is largely ignored by all.
Example: A huge nuclear bomb that destroys entire countries is unlikely to be used preemptively, but small, precise weapons with limited range are much more likely to be used in war and in turn, can result in the big ones to be used too, eventually.

Big Risks Vs Small Risks

A person’s behaviour, once formed, largely remains unchanged. However, a major, life-changing event, that causes hardcore stress, can undo behavioural patterns.
It’s the basis of Post Traumatic Stress Disorder and it makes people change or alter their behaviour, creating new, lifelong habits, scarred by the major event.

Life-altering Experience

Optimism helps us dumb down and decrease the pain and difficulties that the future likely holds, and provides us with hope with regards to our options.
Even now, with the state of income mobility, and the disparity in wealth, few should have reason to be optimistic, but many are, and it doesn’t feel bad to have a positive outlook no matter what the circumstances.

Having A Positive Outlook

When we are ‘hit’ by something huge, and unpredictable, we tend to explain it with great force and start forecasting with greater conviction, as if we know a lot about life. Someone who hasn’t experienced the earth-shattering event will not be on the same page.
Apart from selfishness, self-centeredness and stupidly, a majority of people do not agree with each other due to them having different experiences.

The No. 1 Constant: Disagreement

History is a treasure-house of learning, and as many books teaching us lessons from history point out, what was true in the medieval ages is often true even now, though the circumstances, technology and society have gone through a sea of changes.
The things that are worth knowing are those which hold steady and true then and now.