That bias is the theme of Jeremy Grantham's new quarterly message to GMO's clients.
"As a bear in the bull market of 1999 I was banned from an institution's building as being 'dangerously persuasive and totally wrong!'" the investment legend wrote. "The investment industry also has a great incentive to encourage this optimistic bias, for little money would be made if the market ticked slowly upwards. Five steps forward and two back are far more profitable."
To illustrate how this bias pervades society, Grantham identified 12 ways the US is thought to be a global leader. And in his charting, he reveals how the facts tell a different, more depressing story.
"It is my attempt to bring home how extreme is our preference for good news over accurate news," he said.
We grabbed his charts to give you a quick summary of what he's talking about.