It wasn't a "slap in the face." It was the cake down your piehole.

And if I hear one more time online about Marilyn Monroe was a size 12-16 [and she wasn't] from someone who can't own their own choices, I swear to god...  The absurdity of women’s clothing sizes, in one chart - The Washington Post: "Here are some numbers that illustrate the insanity of women's clothing sizes: A size 8 dress today is nearly the equivalent of a size 16 dress in 1958. And a size 8 dress of 1958 doesn't even have a modern-day equivalent — the waist and bust measurements of a Mad Men-era 8 come in smaller than today's size 00...

Enter the era of vanity sizing. Clothing manufacturers realized that they could flatter consumers by revising sizes downward. The measurements that added up to a size 12 in 1958 would get redefined to a size 6 by 2011. And different manufacturers defined sizes differently, too — this fascinating New York Times graphic from 2011 shows how a size 8 waist measurement could differ by as much as five inches of cloth between different designers."

Vanity Sizing - Different Sizes in Stores: "Some time in the past several decades, designers tapped into a bankable truth: Women tend to feel better and buy more when we fit into a smaller size. "I put on 10 pounds in college and dreaded shopping because buying bigger sizes forced me to admit I'd gained weight," says Naomi,* 25, from Montreal, Canada. "It was like a slap in the face."

...Enter vanity sizing, where designers add extra inches of fabric to clothing without changing the number on the tag. For example, if you measure a size 2 pair of pants today, they might be as wide around the waist and hips as a 4 from 10 years ago. And 00s aren't the result of women shrinking away (though some actresses seem to be). Designers created them because as 4s morphed into 2s and 2s became 0s, smaller-framed women were sized out of the normal range."