Do not apply data science methods without understanding them

I heard a joke from a friend, here is an adaptation:

Three software engineers and three data scientist meet to take a train to go to a conference. Software engineers buy three tickets, data scientists only buy one for all three. “Don’t worry,” they explain to the engineers, “We have a method.”

On the train the three data scientists pack themselves into the bathroom. When conductor knocks on the door they stick the ticket out. Conductor takes the ticket and moves on. All six friends reach their destination without any problems.

On the way back, the three engineers buy one ticket while the data scientists buy none. The engineers are baffled. “We have a method,” explain the data scientists.

On the train, the engineers pack themselves into one bathroom stall, and the scientists into another. Right before departure one of the scientists comes out and knocks on the door where the engineers are hiding. An engineer sticks their ticket out, the scientist grabs it and goes back to his colleagues.

The moral of this story is: Don’t apply data science methods without understanding them