Just realized a silly thing this morning: Due to photography, I know have a feel for grams. 100g differences. What 600g feels like vs. 300 vs. 1000, etc. All due to lens and camera weights. Though I've lived in the US, I never got a real feel for ounces. But, I do know the weight of pounds. I know what 1 pound feels like, or 5 or 10 or 25. But I have no feeling for Kg, unless I first convert it to pounds. Same thing with meters and miles. I know short distances in meters, due to focal distances, but I have a much better feel for miles and fractional miles than kilometers. Maybe the English have always felt this way -- residing as they do between their own system, but so near the Continent. For me, it's all due to my hobby as a photographer. Otherwise, I'd have no feel for metric measures at all.