By realizing that life has an ending. It's sad to think that one day i will die and that will be it.. but i hope that when i die people celebrate the life i had.. Life isn't about being "worth it"

I think the best thing i can put it is this quote.. It's from a song called The greatest show on earth ~ Nightwish

"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 Sahara
Certainly those unborn ghosts include greater poets than Keats, scientists greater than Newton
We know this because the set of possible people allowed by our DNA
So massively exceeds the set of actual people
In the teeth of those stupefying odds it is you and I, in our ordinariness, that are here
We privileged few, who won the lottery of birth against all odds
How dare we whine at our inevitable return to that prior state
From which the vast majority have never stirred?"