We all screw up sometimes. So when you do, do not be too hard on yourself. And if you make a really big mistake, it may calm you down to know, that at least you are not one of the two French scientists who in 1793 were tasked with defining the length of 1 kilometer as 1/40,000 of the earths circumference. They got it wrong, which means 1 meter is off by 2 mm, which means that for all eternity Earth’s circumference is not 40,000 kilometers, but 40,075 kilometers. That one has got to sting.