What is Hindsight Bias?
Hindsight bias is the feeling, after an outcome is known, that it was obvious all along. Experiments show that people who are told an outcome rate it as far more predictable than people who are not told, and they rarely notice the shift in their own judgment.
Why Hindsight Bias matters
If every past move looks obvious, you overrate your ability to call the next one. Writing a reason down before the result is known is the cure.