Hey Sylux, Fenn's ideas are just silly, I have a better idea based on an interesting thing I've been considering recently. As follows:
Consider a social interaction where you and another party want opposite things or you're competing with someone else for a finite resource. There are three 'common-sense' outcomes to this, and each corresponds to an option in the Prisoner's Dilemma.
(a) You take the resource and fuck the other guy. (+2 to you, 0 to him)
(b) You share the resource with the other guy. (+1 to you, +1 to him)
(c) He takes the resource and says 'fuck you'. (0 to you, +2 to him)
Obviously (b) is best for both of you, but (a) is better for you as an individual. They're in order of preference for YOU, so yes, (a) is best - go ahead and hurt others as much as you like, Sylux.
However, there's another option which is even better than (a).
(d) Co-operation; both get what you want (+2, +2)
In theory for YOU it's equally beneficial as (a). However outside of pure game theory it's better than (a) in a number of ways. One, if an action benefits the other actor as well as you, it's more likely to be legal and thus cause fewer long-term problems. Two, you gain social benefit from (d) that you don't obtain from (a), which gives you an intangible but useful resource in solving future problems. Three, if you're not a psychopath you gain the intangible benefit of happiness from helping the other party.
This also defies the prisoner's dilemma and justifies free-market capitalism, option (d), over authoritarianism, options (a) and (c), or ideal communism, option (b).
Or, in your specific case (causing pain), find a masochist and team up with them. BDSM clubs are a likely place but there are others too.