Unlike surgery or engineering, success in finance depends more on behavior than intelligence. A disciplined amateur who controls greed and fear can outperform a PhD from MIT who makes poor behavioral decisions. This highlights that temperament is the most critical variable for long-term financial success.

While technical analysis has its place, true long-term success in markets is overwhelmingly determined by one's inner journey. Mastering self-awareness, emotional discipline, and psychological biases is far more crucial than mastering complex financial models.

True investment prowess isn't complex strategies; it's emotional discipline. Citing Napoleon, the ability to simply do the average thing—like not panic selling—when everyone else is losing their mind is what defines top-tier performance. Behavioral fortitude during a crisis is the ultimate financial advantage.

Post-mortems of bad investments reveal the cause is never a calculation error but always a psychological bias or emotional trap. Sequoia catalogs ~40 of these, including failing to separate the emotional 'thrill of the chase' from the clinical, objective assessment required for sound decision-making.

Even one of history's most brilliant minds, Isaac Newton, fell victim to financial mania. He invested in the South Sea Company, sold for a profit, but then FOMO drove him to reinvest at the peak, leading to massive losses. This demonstrates that emotional discipline, not just intelligence, is crucial for investing success.

Dalio claims meditation is the single most important factor in his success. It provides the "equanimity" to observe market and political realities objectively, separating emotional reactions from analytical decision-making. This allows him to treat all events, even negative ones, as learning experiences.

In 2008, Howard Marks invested billions with conviction while markets crashed, yet he wasn't certain of the outcome. He held the paradox of needing to act decisively against the crowd while simultaneously accepting the real possibility of being wrong. This mental balance is crucial for high-stakes decisions.

Warren Buffett's early partner, Rick Gurren, was as skilled as Buffett and Munger but wanted to get rich faster. He used leverage, got wiped out in a market downturn, and missed decades of compounding. This illustrates that patience and temperament are more critical components of long-term success than raw investing intellect.

According to Ken Griffin, legendary investors aren't just right more often. Their key trait is having deep clarity on their specific competitive advantage and the conviction to bet heavily on it. Equally important is the discipline to unemotionally cut losses when wrong and simply move on.