When we are young, we dream about the future and worry about what we don't have and what will be. When we get older we reminisce about the past and lament about what we don't have and what was. Both of these stages in life have one thing in common- both are not living in moment. I know, easy to say, but hard to do. Here is a video that might help illustrate that for us...
https://www.youtube.com/watch?v=Nq8loZlpa_8