From Killing the Buddha:
You can gain tremendous success in life, raise a big family, have an exciting job, develop a rich spiritual life, spend your time helping others—life offers lots of opportunities for the time we’re here. But no matter how much you achieve, aging, sickness, and mortality are working away, whittling you down to size until the day they finally win for good. Like circling sharks they are always hounding us, harrying even the happiest of lives.
Perhaps the persistent tendency to harden insight into unquestioned doctrine arises from our need to feel secure, to gain a hold on our situation and stave off the fear that things are dangerous and beyond our control. It’s an attitude that naturally appears when dealing with illness, aging, and mortality, the greatest of fears; and the fact that we really aren’t in control, that we can’t wield power over such awesome eventualities, just makes us crave answers and solutions all the more. In a similar way, the modern formulation of the stages of grief popularized by Elisabeth Kubler-Ross offers a guidepost on the way of loss for the bereft, yet if taken literally, it denies how we revolve continuously in these mental states.
A famous Buddhist story tells of Kisa Gotami, a young mother from the Buddha’s clan whose baby boy died suddenly. Grief-stricken, she carried his corpse with her everywhere, wailing and wondering aloud why her child had left her. People pitied her, and eventually she was told to go to the Buddha for advice. When she reached his retreat, she demanded that the Buddha bring her boy back to life. Somewhat surprisingly, the Buddha agreed to do so, but first asked Gotami to do something. “Anything, anything,” she cried in desperate hope. The Buddha told her to go into the village and bring back a mustard seed from a house which had never known death.
More here.