Also, I often wondered whether the US use different preferred numbers for buildings, because everything just feels a little different and out of proportion to me. However, this could also be due to the non-metric system in the US.
My biggest petty complaint is with the 8" x 11" (Letter) paper size and related formats like Legal and Ledger. The ratios are all over the place. The European A0/A1/A2/A3/A4/A5/A6 papers all have a ratio of 1 : 1.414 (square root of 2), so two sheets of Ax always fit exactly into one sheet of Ay where y = x - 1.
I mean, sure, the paper sizes used in engineering in the US have the property that two smaller ones side by side match the next larger size (http://www.engineeringtoolbox.com/drafting-paper-sizes-d_214...) but it's still a pain because it's all denominated in inches. There's no reason for that at all--it's not like there is value in having engineering drawings printed on physical paper with round-inch dimensions--even if the drawings are in inch scale.
So, US people: step up and abandon your paper sizes, because no one else is going to do it.