The Imperial system. It SUCKS. What I hate is how I WANT to learn Metric, but since I was taught Imperial all my life, I'll never know it. Main reason was my Republican father who said "the dumb Brit system is not needed in America".
Sometimes I do wish I'd been raised to think in metric terms, since even with all the crazy 'murrican units, I find myself using some of the smaller units. After all, we don't really have much that can be comparable to millimeters and milliliters and milligrams. o3o
In science classes from middle school to college, you get totally educated on the metric system. BUT THINK OF ALL THE SIGNS WE'D HAVE TO CHANGE! That would be, like a billion dollars! WE WOULD NEVER RECOVER! Maybe we can get rid of the penny, and then use the money we save from that to change all the signs.
That wouldn't work either. If both types of signs were up at once, it would be too easy for drivers to mistake a 40kph sign for 40mph sign, and going 40mph in an area where you're only supposed to go 25mph could be really dangerous. The only real way to avoid this would have all of the street signs switched at the same time, which would be a really difficult project. Oh, well. I really like the metric system.
But then only the East Coast would get new signs, and the rest of the United States would be stuck without the metric system forever. And they would get jealous of the East Coast for having the metric system. And the East Coast would be shunned by the rest of the country. And the rest of the country would plot to destroy the East Coast and steal their signs.