Imagine I give you a $100 check that is good in ninety days. Then I try to bargain you down: Would you be willing to trade it in for a $50 check that is good today? Most people would not. However, if people are first given the $50 check, and then asked if they’d be willing to exchange it for a $100 delayed reward, most will not. The reward you start with is the one you want to keep. One reason is that most people are loss-averse — that is, we really don’t like to lose something we already have. Losing $50 makes people more unhappy than getting $50 makes them happy. When you think about a larger, future reward first and consider trading it in for a smaller, immediate reward, it registers as a loss. But when you start with the immediate reward (the $50 check in your hand) and consider the benefits of delaying gratification for a larger reward, it also feels like a loss.
— The Willpower Instinct (Kelly McGonigal), Loc. 2505–12