In the U.S., measurement is all about feet, ounces and Fahrenheit. Most everywhere else, however, people use meters, liters and Celsius. American devotion to their archaic system, called the U.S. customary system, dates way back to 1821 when then-Secretary of State John Quincy Adams said thanks, but no thanks, to going metric. President Andrew Johnson signed a law in 1866 that allowed contracts, court proceedings or dealings to use the metric system, but it failed to take off.
In 1975, the Metric Conversion Act was passed, along with the Trade and Competitiveness Act of 1988 making another attempt at encouraging adoption of the system. The inherent problem is that all of these "laws" are "voluntary," meaning that states, businesses and anyone else can adopt the system if they want to, but they don't have to [source: Guzman].
It's a pain in the neck to learn a new measurement system, so who's going to do it if it's not mandated? (Government mandate is how the metric system took hold in many countries. The U.K. went metric in the 1960s.) Experts claim, however, that failure to fall in line with the rest of the world makes doing business ultra-confusing and actually hurts the American economy [source: National Institute of Standards and Technology]. Oddly, the metric system has taken hold in some corners of the U.S. economy — such as the 2-liter soda. Which brings us to our next difference.