Robert C. Solomon, a well-known professor of philosophy at the University of Texas who died in 2007 of heart failure at the age of 64, used to tell the following story from his own personal experience...
He was a medical student at the University of Michigan when by chance he walked into the wrong crowded lecture hall. He had been unhappy with his medical studies when something the lecturer said caught his attention. The professor was lecturing about Nietzsche's idea of the eternal return and the the fundamental question:
"If given the opportunity to live your life over and over again ad infinitum, forced to go through all of the pain and the grief of existence, would you be overcome with despair? Or would you fall to your knees in gratitude?"
That very day Solomon went and changed his major to philosophy and would eventually become one of America's foremost experts on 20th Century Continental Philosophy and phenomenology.