actually while a person lives they may build character, but the time always comes when they screw up in one way or another, then all of that is tossed out the window and you actually have a deficit of character. Lets say you live your life as a wonderful person who always tells the truth, then you, I don't know, betray someones trust. Now all the great things you did don't matter since human nature dictates that we always notice the bad and not so much the good, thats how Fox has survived as a television channel. Instead you will lose face. Since after you die you cant screw up this inevitable screw up will be halted and you will be built up to an amazing human and retain your brilliance instead of falling. Basically, what goes up must come down, so if your dead there is no more fall. As for the part about existence being meaningless, that may be true, and without interaction no one will even remember you, but unless your like a Jeffrey Dammer than even if you don't contribute anymore you still will maintain the illusion that you do matter and to say otherwise is a societal taboo.
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Foolish Mortals