In his response to Phillip Raskin’s question about paper sizes, Cecil mentioned international standards. These are well explained in http://www.cl.cam.ac.uk/~mgk25/iso-paper.html which also gives more on the history of US paper sizes and the inconvenience they cause. The same author has provided a most readable paper on time standards http://www.cl.cam.ac.uk/~mgk25/iso-time.html.
I write from UK, where we try hard to equal the US in our reluctance to adopt standards however much easier they could make our work. For no good reason, we stick to the old 12 hour clock and have to add am or pm. Some opponents of change describe Fahrenheit as the British way of stating temperatures. It was named after a German scientist!
UK set about going metric in 1965. Some of the few other non-metric countries noted this and made the change quickly to protect their trade positions. They need not have rushed. We are a long way from completing metrication. I have an 1849 coin issued in our first attempt to introduce decimal currency. We finally got there in 1971, so we may be metric some time this century!
To learn more about the mess we are in have a look at http://www.ukma.org.uk/