Womens sizes... like Jesus Christ, I don't know how ANY women tolerate this shit. It's completely made up. A size 0 in one brand feels similar to a size 3 in another, feels similar to Large in another, feels similar to -1 in another. Anything you buy and like, you effectively have to pray they keep making forever, and always buy from that brand or you risk getting something else that doesn't fit correctly.
I've never shopped a product category that feels so utterly hostile to consumer comprehension, except MAYBE microtransactions in videogames. And I'm not meaning to be dramatic, that's the only other type of market I've experienced in life where it feels like my attempts to understand what I'm buying are being deliberately frustrated like this.