From an article by Belle Beth Cooper in Fast Company titled 8 SUBCONSCIOUS MISTAKES OUR BRAINS MAKE EVERY DAY–AND HOW TO AVOID THEM …
“The term sunk cost refers to any cost (not just monetary, but also time and effort) that has been paid already and cannot be recovered. So it’s a payment of time or money that’s gone forever, basically.”
“The reason we can’t ignore the cost, even though it’s already been paid, is that we are wired to feel loss far more strongly than gain.”
For instance, if you buy a movie ticket only to realize the movie is terrible, you could either:
A) stay and watch the movie, to “get your money’s worth” since you’ve already paid for the ticket (sunk-cost fallacy)
B) leave the cinema and use that time to do something you’ll actually enjoy.
The thing to remember is this: You can’t get that investment back. It’s gone. Don’t let it cloud your judgment in whatever decision you’re making in this moment–let it remain in the past.