The sunk cost fallacy is perhaps the most useful thing you learn in business school. eg. Do I want to pay $9,600 to get the job finished. What would it cost if

The sunk cost fallacy is perhaps the most useful thing you learn in business school. eg. Do I want to pay $9,600 to get the job finished. What would it cost if I hired someone else to finish it ? The same thing if you are going to a concert and lost your tickets, do you want to pay $200 to go to the concert (not taking into account that you've already lost $100, you could have lost that $100 on whatever) eg. you are paying 200, not 200+100.