Recall from the discussion of the endowment effect that all economic decisions are made through the lens of opportunity costs. The cost of dinner and a movie tonight is not fully captured by the financial outlay—it also depends on the alternative uses of that time and money. If you understand opportunity costs and you have a ticket to a game that you could sell for $1,000, it does not matter how much you paid for the ticket. The cost of going to the game is what you could do with that $1,000. You should only go to the game if that is the best possible way you could use that money.
