Originally Posted by
Redmayne 
There is a suggestion in Zen Buddhism that we should, 'Die while alive'.
My understanding of this relates to Buddhist thought regarding attachment. Attachment, in this view, is the cause of suffering. As people strive to hold onto things that they have, they have fears, anxieties and feelings of loss which can make life quite unpleasant. "To die while alive" is a metaphor. It's a metaphor for giving up all attachment and in the process gaining, a deep realization (and acceptance) that every
thing is transitory.
For me, this notion is also closely related, in spirit, to in the serenity prayer.