I read a quote from Jon Stewart given as part of a commencement address in which he said that life is an elective, not core curriculum - I like that.

Edited to add the quote:
Quote Originally Posted by Jon Stewart speaking at the 2004 commencement of the College of William and Mary in Virginia
" The unfortunate, yet truly exciting thing about your life, is that there is no core curriculum. The entire place is an elective. The paths are infinite and the results uncertain. ... Life is something you experience."
It got me thinking about all the other phrases I've heard that begin with "Life is ..." or "Life's ..."

So, essay question. Life is _________. Discuss!