When Sunk Costs Help
"When the costs of our past financial decisions can't be recovered, they're considered "sunk": like when Rose drops that fancy necklace into the water in Titanic. (Why'd she do that, anyway?...)... We typically think of the sunk cost fallacy as something bad: something that creates sub-optimal, illogical behavior. But in the case of my sister's gym membership, it's increasing a healthy behavior. She's going to the gym more often, because she doesn't want that $70 to go to waste."
Check out the entire post here: DonebyForty.com