Guys, am I the only one that doesn't get the breast size measurements?

Or hip circumference measurements, I just don't understand them, not even the letters make sense, like 3A, one time I went online and added "D" to a number to see how many Ds I can add before I reach a size that doesn't exist, am I suppose to know by seeing them? Do women know by seeing them? Or do they know by the bras they buy? Now pants, don't even get me started on the pants measurements, I know how to measure them but can't guess for shit
Guys, am I the only one that doesn't get the breast size measurements?
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