“Every past market crash looks like an opportunity, but every future market crash looks like a risk,” writes Morgan Housel in a recent blog for Collaborative Fund.

Housel offers insights as to why investors tend to attach more to negative thoughts than to positive ones, why pessimism is more “seductive” than optimism. Pessimism, he writes, “can be hard to distinguish from critical thinking and is often taken more seriously than optimism, which can be hard to distinguish from salesmanship and aloofness.”

According to Daniel Kahneman, 2002 Nobel Laureate for his work in the field of behavioral economics: “Organisms that treat threats as more urgent than opportunities have a better chance to survive and reproduce.” Wharton professor Jeremy Siegel, writes Housel, who is known for his investment optimism, argues that investor pessimism can be based on too short a period of experience, that they should look at periods of longer than ten years when considering performance.

“Since short-term shocks are more frequent and recent than long-term gains,” he adds, “pessimism usually sounds smarter than optimism because it’s easier to recall.”