One stock is an apple. If the apple is good, you eat well for a day. If it isn’t, you eat nothing. A portfolio is a bowl — apples, pears, grapes, whatever’s in season — built so no single piece of fruit decides the meal.

Concentration feels safe because it’s simple to understand: one company, one outcome. It’s risky for the same reason. Diversification isn’t about giving up on your best idea — it’s about making sure your best idea isn’t the only one that has to work.