destiny, or prediction?

If I had the choice of learning (or not) when and how my death would occur, I'd want to be told, but I would doubt, and then I'd probably kill my stubborn ass the day before just to prove "them" wrong. In science, one can't assume that even watching something take place doesn't necessarily affect the outcome. which brings up a point that was illustrated in the film "stranger than fiction" - if one knows about death's approach, one has the ability to try to avoid it. That makes me wonder: is it really knowledge? Or would one just become some demented freak trying desparately to convince him/herself that mortal existence is worthwhile? If all attempts to avoid the impending death prove futile, then what has the individual accomplished any more than an animal that only understands the race to save its own skin? And if one is able to miraculously cheat death, what good is that? In order to really, truly care so much about the time and place of death, one would have to be pretty selfish in imagining themself to be above the mortality of everyone else, or else insanely altruistic and only want to spend one's time helping others.
That, of course brings me to the question: If our purpose on Earth is to help others, then what exactly are the "others" here for?