Loss Adversion
The tendency to prefer avoiding losses over acquiring equivalent gains.
Schell describes Kahneman and Tversky's Prospect Theory as applied to games, in that players will be willing to pay a premium to avoid losses - they may take a lower Expected Value option if it means less chance of regret. Even more surprising, players will be willing to take risks to avoid losses. Think of a gambler who lost a little money, they may be willing to gamble more money to avoid a little regret. Further described in Wikipedia article on Loss adversion.
References: