Torture.
It's an extremely ineffective way to get information. If the person who's being tortured has any sense at all, they'll just say whatever they need to to get the torture to stop. I've gotten out of a few tights spots myself by lying while being tortured.
On the other hands, if the torturer isn't looking for any information, if they simply are torturing you for the pure intent of wanting you to hurt... Well. Torture is generally more effective then.
While of course it's painful during the actual act of torturing, depending on the method used, the effects of torture can last long afterwards. You may have lasting scars for the whole world can see. You may have some brain damage or some other internal organ damage. Whatever the case, you can be sure that you're going to be completely exhausted for days, if not weeks, afterwards.
A/N: I love reviewers and live for constructive criticism!