Fantasy football is an imaginary game with real-life implications. While the players on NFL teams out of a playoff spot can choose to make business decisions to ensure they don't miss an island vacation, fantasy managers don't have that luxury. More often than not, there is no No. 1 draft pick prize attached to a season of mediocrity.
Instead it often comes with shame and punishment for finishing at the bottom of the standings. Whether that's doing some humiliating forfeit or a variety of other factors, no one wants to finish last, not even the nice guys.
Start or sit decisions become key for that very reason.