I think about this [How does it make you feel to think about the day you're going to die?] all the time. It literally keeps me awake most nights, laying here alone in the dark, thinking: one of these days, I'll feel my heart stop, feel my lungs fail, and there will be nothing I can do about it...
I start to tumble down a slippery slope, most of the time. I look up at the ceiling and wonder what it was like for all the people I know who have died; I wonder what their last thoughts were and what it felt like. Whether they were at peace, or if they had regrets, or if they just felt like the world would be better if they had had one more day.
And that's the irony, isn't it? We waste time everywhere. We deny relationships, we pass up opportunities, we spend more energy thinking of reasons not to do something than it would take to just accept the chance and go for it. We get so busy forgetting we WILL die, that we forget to really live.
And sometimes I get very depressed over it - not in the sad sense, but in the whole, "nothing I do ultimately matters" sort of way. I think to myself - I could unify the world, I could bring together every last person in harmony; they could melt down all the statues of generals and warmongers to make one of me, the Great Peacekeeper; they could build the tallest building that ever was or will be, and dedicate it to me; I could be hailed as the greatest man who ever lived...
My bones will rot next to those of the poorest beggar that ever was. However high I may be raised in life, my children's children will still walk over my grave while they carry on. The atoms that constitute my ashes aren't gold-plated, or impervious to time's relentless march. And even if they were, there will come a day far in the future when the sun - which allows us to live for the moment - grows tired of us and expands past our orbit, obliterating everything that you, or I, or anyone you have ever heard about or imagined has ever done.
And you'd think that would make it worse. But, hear me out...it helps.
Death is the great equalizer. As Ray Kurzweil wrote, it gives importance and value to our lives, to our time. Without it, eventually everything would become stale and meaningless. When it comes, it may be unwelcome but you can at least take solace in the fact that whoever died is most decidedly not alone.
Out of all the things to experience in this world and this life - out of all the places to be born, to live, to love, to laugh in, all the paths to walk and friends to make and emotions to be felt with unrestrained force - there is only one universal that everyone will face. Death reminds us all that we are in this together, and even in the shadow of such an overwhelming fear, we are not alone. Billions have gone before us; billions will follow. It binds us much more than it separates us.
For the man who has gone onward, pay him respects. He went before his time and that is unfortunate; but take comfort in the fact that his troubles are over. He'll never get cancer, he'll never be homeless, he'll never lose everything in a bad marriage.
For the living, take it as a reminder that in the grand scheme of things, a lifetime is not that long. Some people do more in 28 years than others do in 100. The universe holds no opinion either way, and it would have been much more likely for you to not exist than to be here reading this. Embrace the improbability of your sentience, and make the most of this one life you have, because not everyone gets the chance.
Go jump out of a plane, go learn Cantonese, go have a wild night with your best friends. Consider them all to be the last things you do, and be happy with it all. Understand that pain is necessary to truly comprehend how good it feels when you don't hurt anymore - there can be no light without darkness. But when that light comes back, everything will be clearer, more defined, and much more meaningful.