Perhaps now more than ever, forecasting the short-term trajectory of the market has become an exercise in futility. Rapid technological developments, geopolitical disruptions, and black swan events like the pandemic have made it all but impossible to project where we are heading with any certainty.

Amid these upheavals, investors have understandably sought stability. This pursuit has led many to look every which way for explanations as to why their assets are underperforming—whether that’s current events, investment strategy, or the fees and funds tied to their advisors. But in most cases, the greatest drag on returns is closer to home than they might realize: it’s their own behavior.

Rash decisions made in response to market trends…