Though designed as a mere convenience, clothing sizes establish an unintended norm, an ideal from which deviations seem like flaws. There's nothing like a trip to the dressing room to convince a woman - fat, thin, or in between - that she's a freak.

Clothing creates the illusion that bodies fit an aesthetically pleasing norm. And that illusion depends on getting the fit right. Garments that bunch, pull, or sag call attention to figure flaws and often make people look worse than they would without clothes.

Standardized sizes made inexpensive, off-the-rack garments economically feasible. They gave shoppers a reliable guide to finding clothes in self-service shops.

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