Variance is not the full definition of risk; it is just the easiest part to measure. Core idea: A smooth path can still hide fragility if the losses are rare but severe. A noisy path can still be healthy if the downside is bounded and compensated. Why it matters: That is why investors need a vocabulary that separates discomfort from permanent impairment. In real life: A portfolio of option-selling income strategies can look calm right until hidden tail risk arrives. Common slip: The error is equating low day-to-day volatility with actual safety. Try this: On the next review, write down the one variable that would make you change your mind. That is usually where the edge is: not in the vocabulary, but in the structure underneath it.