Past - Sometimes we're reminded of the past. Sometimes we live the past all over again. The thing about past is that its definitive - obviously - that's something that's already happened.
Future - Sometimes we think about future. Sometimes we're afraid of the future. Sometimes we're eager to see the future. The thing about future is that its not definitive - again obvious - that's something that has not yet happened.
What about "present"? It was the future of the past and would be the past of the future. The thing about present is that no one can take it away from you. Sometimes we fail to realize this. I have failed to realize this. I don't know if I have realized this yet.
You are young and life is long and there is time to kill today
And then one day you find ten years have got behind you
No one told you when to run, you missed the starting gun
Time - the beginning
Time - the end
And all that's in between...