" The greatest difficulty that many people face, as we have seen, is in admitting to their personal failures, and thus learning from them. We have looked at cognitive dissonance, which becomes so severe that we often reframe, spin, and sometimes even edit out our mistakes. Now think of the Unilever biologists. They didn’t regard the rejected nozzles as failures because they were part and parcel of how they learned. All those rejected designs were regarded as central to their strategy of cumulative selection, not as an indictment of their judgment. They knew they would have dozens of failures and were therefore not fazed by them. But when we are misled into regarding the world as simpler than it really is, we not only resist testing our top-down strategies and assumptions, we also become more defensive when they are challenged by our peers or by the data. After all, if the world is simple, you would have to be pretty stupid not to understand it. "

― Matthew Syed , Black Box Thinking: Why Some People Never Learn from Their Mistakes - But Some Do