This is because you are more strongly (individually, not the whole of our species) to maximize your survival opportunities than your pleasure opportuinities. If it is the case, for instance, that you would accept to become an entity with a constant focus of attention into almost nothing (a meditating entity) instead of having loads of fun for one fourth of the time (say, 1000 versus 4000 years) this means you are a survival optimization process. You were not designed for this, you were designed to maximize genetic fitness. And you were designed to maximize memetic fitness. You have been designed by two major forces composed of many many minor forces. You have decided, morally, to abdicate all this plurality in the name of conscious survival. You praise individuality, and you praise persistence. I would suggest to let one more meme take over your mind. The meme of fun. Optimize for fun, don't lead us into a universe of "sperm donors" who detect minimal entropy spaces to be at for longer. Don't lead us here: http://www.nickbostrom.com/fut/evolution.html