Who never claims sizes are evil? And I don't believe it is only when we have to go and pick a larger size than expected...
I hardly ever shop or use normal patterns, so I tend to forget about this particular issue. However, I do sometimes buy second hand/vintage clothes. I usually don't look at the size on the label. I concentrate instead on material and shape/style or refashion potential.
In my previous post I, and some of you, already mentioned how different fashion eras champion different shapes and ideas of fit. This is an issue you definately come across when shopping second hand.

I bought this silk ladies' shirt for 1 euro several weeks ago. According to it's own size tag, it's a size S and it was made in China. I think, based on the style and that rather generous size (it's on my old dummy here, which is larger in the bust than I am. I still have to find some legs for Mary) that this is an 1980's garment. I like the Chinese knot detail of the closure and thought I might try to wear it as is. But I haven't yet. Even belted, it just feels too bulky. I'm thinking of re-setting the sleeve to narrow the shoulder but it might need yet more work. It's lovely smooth, light and soft silk, so it would be worth the effort.

This shirt is also silk and I bought it today at the same market stall. This material is less finely woven, resulting in a shirt which feels smooth and has a cotton-like hand. According to it's size tag, this shirt is a size 40 and made in "W.-Germany". I'm not sure how to date it. The fact that it was made in West-Germany means it has to be pre-1990, of that I am sure. Although it's undarted, it seems too closely fitted for an 80's shirt. On the inside, both shirts are finished with the same 3-thread serging. The style of the collar doesn't look recent.
And, crucially: size 40??
German sizes are the same as Dutch size and if this shirt was in a shop today, it might make quite a few women comment on the evils of sizing. It's a bit wide on me, but fits about right at the shoulder. Usually, a size 36 will fit me at the shoulder.
I should really do a proper post about RTW sizing, size-inflation etc., some day soon. But I have to think on that a bit longer... For now, I'm just curious about your ideas about the dates on my shirts, your tales of strange sizing and, if you feel particularly helpful, any tips on what to do with shirt number 1.