I know whereof you speak, Jason. I've had a hobby woodshop for many
years and have done some house and fence fixup jobs. The measurement
units problem leads to some enlightening episodes involving immigrant
workers. Most US-born construction workers question the ability of
the immigrants, but they're rendered speechless when the immigrants
do calculations in their heads such as dividing 5 feet 3 inches into
four equal parts.
When we finally complete the shift to metric units in this country I
believe the biggest impact might be on office workers. It boggles the
mind to think of using A4-sized paper instead of 8 1/2 x 11 inches.