Does guilt affect performance? Exploiting a novel measure of the justificationof penalty calls, we find that unjustified penalty calls negatively affect penalty conversion rates, and that this effect increases with social norms of trust. Exploiting the variance arising from players who do not play in their countries of origin by including the norms of both the league and the kickers’ countries of origin, we separate the constraints on egoism into two categories: internal sanctions, such as guilt, and external sanctions, such as shame. We find that both guilt and shame affect the performance of penalty kickers.