The article explores how different types of time discounting affect strategies in repeated games. They focus on games with perfect monitoring and symmetric stage games. The researchers identify the harshest punishment strategies for players with future bias and present bias. They find that the worst punishment payoff can vary based on the type of bias. In some cases, the worst punishment payoff can be higher or lower than the stage game minmax payoff. As the length of game periods approaches zero, the researchers also analyze the set of limit equilibrium payoffs.