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xkcd #3232: Countdown Standard
(imgs.xkcd.com)
xkcd #3232: Countdown Standard
Title text:
Anyone who is caught counting 'three ... two ... one ... zero ... GO!' will be punished with a lifetime of eating only ISO standard food samples.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3232/
Another problem is that system requires agreeing on what a week is, and there's disagreement over whether Sunday starts or ends the week.