Investors often start new positions too small due to myopic loss aversion. A powerful nudge is to set a default entry size for all new ideas. While deviations are allowed, requiring a manager to explicitly document their reasoning for going smaller introduces "process sludge" that forces more rational thinking.

Like a poker player after a bad beat, investors who suffer a big loss are psychologically tempted to make increasingly risky bets to recoup their money quickly. This "on tilt" mentality, exemplified by Edward Gilbert, shifts focus from sound analysis to desperate, high-risk gambles that usually compound losses.

When selling a losing position during a drawdown, it's crucial to determine if the decision is driven by the emotional inability to endure more pain (pain management) or a rational assessment of future risk (risk management). Confusing the two leads to poor outcomes.

From the book "Art of Execution," the most destructive investor type is the "Rabbit," who freezes when a position drops. This inaction is dangerous because they fail to cut losses or reassess their thesis, allowing losses to compound significantly.

To combat the emotional burden of binary sell-or-hold decisions, use the "Go Havsies" method. Instead of selling a full position, sell half. This simple algorithm diversifies potential outcomes—you benefit if it rises and are protected if it falls—which significantly reduces the psychological pain of regret from making the "wrong" choice.

A powerful risk management technique is setting a maximum percentage of your portfolio that can be invested in a single stock *at cost*. A 5% at-cost limit means once you've invested 5% of your capital, you cannot add more, even if the stock price plummets and its market value shrinks. This prevents chasing losers.

Based on Daniel Kahneman's Prospect Theory, once investors feel they are losing money, their behavior inverts. Instead of cutting losses, they adopt a "double or nothing" mentality, chasing high-risk gambles to escape the psychological pain of loss.

Emotion drives poor financial decisions. Negreanu notes the biggest leak for most players is their session length. They'll play for hours trying to "get even" on a bad day (when they're likely tilted and playing poorly), but cash out after a small win on a good day (when conditions are favorable).

To avoid emotional decision-making, especially with losing positions, write down the specific criteria for any investment. Then, backtest those rules against historical data. This replaces emotional struggle with a systematic, data-driven process.