Reading your post got me thinking of a quote:

"We are going to die, and that makes us the lucky ones. Most people are never going to die because they are never going to be born. The potential people who could have been here in my place but who will in fact never see the light of day outnumber the sand grains of Arabia. Certainly those unborn ghosts include greater poets than Keats, scientists greater than Newton."

So if we are the lucky ones because we are alive we have to do the most of it, that is my biggest motivation.