What is the "winner's curse"?
In a bidding process, the winner of the bid is likely to be the party that most overvalues the object being bid upon. Hence, the winner of the bid will likely overpay, making winning an auction actually a curse.
In professional sports, after a team wins the championship they have a huge target on their back as everyone is trying to defeat the champions. Hence, a curse develops as it is extremely hard to continue winning.
Once a team wins a championship and celebrates, they become less focused on winning again.
The winner of the draft lottery will have to finish last in the previous season. Thus, to be a winner (in getting the best talent ) you have to be cursed in playing the game. '