There are answers to this.
Buying clothes and trying to slim them down has taught me both my measurements and the measurements of the clothing I want. Thigh measurement is an important measurement for raw denim, especially slim, low rise cuts. Common advice is to size by your thigh or to size up for your thighs for certain brands / cuts. Also, thigh size is a point of pride / consternation among lifters / athletes. You become really aware of it when you start working out and those first 3 bottoms you bought when you joined SF no longer fit. How you missed all of this must be some sort of perfect storm of unaware swirling about you.