Here is one well-known counterexample.
https://www.investopedia.com/articles/trading/08/turtle-trading.asp#:~:text=The%20Turtle%20Experiment,-By%20the%20early&text=Dennis%20believed%20anyone%20could%20be,to%20finally%20settle%20this%20debate.
But often, perhaps most of the time, teaching that...