Oh so I know about the shoe one. The sizes are standardised in length but not in width so you can have narrow fit and need a larger length in one shoe, or wide fit and a shorter length in a different shoe.

So the shoes are standardised (sort of, Europe and the US have 2 different standardised systems), but the standard is so confusing it may as well not be a standard.

For 20 years i buy pants size 32. They always fit. But yeah, somehow my work pants are size 46 to 48 for some reason. M is often to big on the waist and S is tiny.