Why Smart People Do Dumb Things

Why do smart people do dumb things? From my experience, these are the most common culprits:

1. Sunk cost fallacy — “I’ve invested so much in this I can’t change course now.”
2. Confirmation bias — You believe what you want to believe.
3. Disconnected from ground truth — You have wrong assumptions about reality.
4. Man with a hammer syndrome — “To a man with a hammer, everything looks like a nail.”
5. Self-serving bias — “It is difficult to get a man to understand something, when his salary depends on his not understanding it.”
6. Overcomplicating — “I will always choose a lazy person to do a difficult job because a lazy person will find an easy way to do it.”