In April 1912 a ship hit ice. Of the 2,224 people aboard, around 1,500 died. There were not enough lifeboats, and several of the boats they did launch went out half empty. Who got a seat was not random.
A decision tree knows none of this. It knows a table: who was on board, and who walked off. Give it the table and it finds the pattern that separates the two. The pattern is the uncomfortable part.
You are about to put yourself in the table.