Jimmy Doolittle, says Ray, introduced the idea of trusting your instruments instead of relying on your intuition. We need to do this for spreadsheets too.
Experiences are deceiving:
Ray says people often cite him saying “spreadsheets are error-prone”, but he never said that! Humans are error-prone.
We think we view the real world, but the real world is messy, and what we see is a beautiful simplification of it: a constructed reality. For example: apparently, once an hour, when driving a car you hit the wrong paddle. Because it is not important, you do not remember this.
Ray related this to Thinking, Fast and Slow. Because spreadsheets are fast, people seem to rely to system 1 thinking, which leads to overconfidence. Independent of the domain, simple but non-trivial cognitive actions will have an error rate of 1 to 5%: