Hmm. In the Prisoner's Dilemma (Axelrod payoff matrix) —
Your actions control your opponent's score more than your own.
You can increase your opponent's score (by 4 or 3) by decreasing your own (by 1 or 2).

Given opponent C, my choice makes only 2 points of difference to my score, but 3 points of difference to the opponent's score. Given opponent D, my choice makes only 1 point of difference to my score, but 4 points of difference to the opponent's score.