On Death and Dying

Nobody wants to die. Well, that's not quite true. After all, lots of people take their own lives. I can't get into the mind of a suicide, but I wonder if it's simply that they want out of whatever situation they are in. They don't seek death, per se, but escape. And people who are in great pain seek death sometimes (but only sometimes).
On the whole, though, we resist death. But why? There seems to be a paradox here. If death is the way of life, why fight it? After all, we have to make room for the next generation, and someone has to feed the worms.
This paradox is most evident in religious thought. I was listening to bluegrass this morning (always makes me think on death and dying). The singer was singing about his mom and dad who were rejoicing around the throne of God. The chorus, however, went, "I'll live my life in sorrow, now that mommy and daddy are dead."
And of course Shakespeare weighed in on it. In a dialogue in, I think, The Merchant of Venice, the fool talks to one of the characters whose brother has died. The dialogue goes something like this (fuzzy quote alert):
"I think your brother is in Hell."
"I know my brother is in Heaven, fool."
"The more fool you, to grieve for your brother's being in Heaven."
If you don't believe in God or an afterlife, not wanting to die is understandable. After all, as W. E. Henley said, after life "looms the horror of the shade." Non-existence is almost too dreadful to be contemplated.
Yet, neither religious nor non-religious thought really makes any sense. Either we go to an eternal reward with angels and gold streets or we simply go out, like a light turned off. No big deal either way.
So why do thoughts of death consume us so?