There are some who believe that when you die you go on living for eternity, perhaps in paradise. Although the thought of your life ending might seem terrible, lets think about living forever.
It's hard to really grasp things like eternity, but I will attempt to put it into perspective the best I have been able to.
Think about how long you've lived so far. Now double that. As long as you have lived, you would go through that time period one more time. Really think about that for a moment. Now quadruple it. As long as you've lived, you would get three more of those time periods. This would probably put most people reading this well beyond average human lifespan. Now take as long as you've lived and multiple it by a trillion for every atom in the universe.
This is a very long time. At this point the current age of the universe would be a very small fraction of 1% of your life. So small a percentage I would run out of memory before I could type out all the 0's that go after the decimal point and before the 1. The 4gb of memory on this computer would not even come close.
On a time period like this, all the music with all the possible sounds and note combinations would have been written. Even the ones that don't sound good. Every possible book would be written. Even the ones in which the letters don't combine to make any sense. Every conversation you could ever had would already be had, there would be no more combination of words to put together that you hadn't heard yet. You'd have met every possible person that human DNA could create. You could have played every possible game of chess and poker.
If you lived in a castle with a million rooms you could have explored all those rooms by now, and spent 100 years in each one. You could count the atoms in the universe at a rate of 1 per year.
You could have done all these things, and you would have finished them a long, long time ago. Now as old as you are now, do the same operation again. Take this life span, and multiply it by a trillion for every atom in the universe. After all this time you haven't made any progress whatsoever in completing .01% of your life.
Someone asked me why I think I will stop existing after my life here on earth is over. I don't know that you don't go on existing after you die, but I certainly hope that it does.