One of the major misconceptions about correlation is that a relationship between two variables means causation; that is, one variable causes changes...

One of the major misconceptions about correlation is that a relationship between two variables means causation; that is, one variable causes changes in the other variable. There is a particular tendency to make this causal error, when the two variables seem to be related to each other.

What is one instance where you have seen correlation misinterpreted as causation? Please describe.