A Marcus Aurelius quote changed my life when I was a teenager. It was something like, "it is not dying that a man should fear, but a man should fear never having lived at all."

From that point, I pushed myself to live -- got seriously into primitive technology and wilderness survival, traveled to many parts of the world, and did many other things that I previously wasn't able to do. I just found my old copy of Meditations in a box yesterday and plan on reading it again.