And when you look at the sky you know you are looking at stars which are hundreds and thousands of light-years away from you. And some of the stars don't even exist anymore because their light has taken so long to get to us that they are already dead, or they have exploded and collapsed into red dwarfs. And that makes you seem very small, and if you have difficult things in you life it is nice to think that they are what is called negligible, which means they are so small you don't have to take them into account when you are calculating something.