[evil-olive]

for another example of this: a lot of people "know" that the average human body temperature is 98.6 degF.

that extra decimal point gives people false confidence about the measurement being more precise than it is.

because so much science (even in the US) happens using the metric system, the actual measured average [0] is 37 degC, and 37.0 degC == 98.6 degF. the nuance of the average being more of a confidence interval (37 +/- 0.5 degC, possibly larger) gets lost as well.

0: https://en.wikipedia.org/wiki/Human_body_temperature