What I am really curious about; Some people say that there can be no day without night, or no pleasure without pain. let's take a drug abuser for example; he needs more and more heroine or whatever if he is using it on a regular basis, to be able to shoot endorphines to the same level he did the first time he tried it. his biology and psychology get used to it, so if he took the same dose every day for a year, his pleasure meter would be declining, unless he would take proportionally larger and larger doses to maintain his level of pleasure. In my opinion, our brain is extremely flexibile and ADAPTIVE, considering the one's pleasure or pain. Perhaps our brain is pre-set to first determine pleasure/pain symbiosis on the base of what's PHYSICALLY good or bad for our body, but i think we have the ability to make our own frontiers through the force of our will. Masochists may prove that in most straightforward manner. Or some holy men or you know-people-who-walk-on-little-fiery-bits-of-wood. My q is actually such; If me or you would be doing every single minute of our existance a thing that is considered the best to experience and that brings the most joy, would it not our brain make sure, that the lower limits of this joy become our pain, thus creating a new equilibrium? Is it even possible to experience joy, if there is no mirror held for our brain so it can consider the opposite, or to make it relative to something?