I agree with you Phil about a base 12 system being more natural and flexible. I am fully fluent with both systems, having been educated and worked as a carpenter in the States, lived and worked in Canada in a mixed system and spent the last six years in Europe. I can judge distances and weights equally well in both the Imperial and the Metric system.

If I had my druthers, I'd build furniture in Imperial, division of spaces is easier in feet, inches and fractions. For temperatures, I hate that water freezes and snow falls at -32F. That makes no sense to me. But when it's hot out, I can relate more to 98F, than to 36C! I mean 98 is a big number, it sounds HOT. 36 is like nothing.

For driving I think I like the metric system, but it doesn't matter much. On a long drive converting distances and ETA's and gas mileage in my head passes the time. The gas mileage system in metric sucks- liters per 100 kilometers is not easy to compute. Why don't we use kilometers per liter?

To me, volume and weights are better in the metric system. I never did get ounces, cups, pints, even before I'd been exposed to metric. Basing weights and measures on the weight and volume of water makes sense. One litre of water weighs 1 kg and has a volume of 10 x 10 x 10 centimeters. It's logical and as water is such a common compound and so important to human life it seems a natural way to relate to the world. It's no more arbitrary than the length of King John's dick or whatever.

I don't think the US needs to completely convert to metric. The Imperial system works, it's expensive to change over and there are more important things to spend money on.