It's not really that difficult to master SI units, my kids seemed to catch on in elementary school without much trouble. Next time you see a commercial electric motor (in the U.S.), take a look at the nameplate and see what units are used for the temperature ratings and the temperature rise.

BTW, performing some engineering calculations in english units is actually a PITA, ask any first year engineering student to explain F=ma in english units and you will start hearing about "slugs" and the difference between pounds (force) and pounds (mass). It won't be pretty.

Another example:

1 newton-meter = 1 joule
1 foot-pound = 0.0012850675 BTUs

It's just like learning another language (something else americans can't seem to handle), you just have to think in SI units instead of trying to translate everything back to english units (i.e., 80C = good, 120C = bad).

BTW, angles are measured in radians, not degrees, for any type of analysis; and both radians and degrees are dimensionless so they are neither english or SI units. Degrees are just arbitrary numbers, but radians are driven by the math and would be the same in any system of units.