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