There was this cool person I met yesterday that told me not to live my life with "could have's, and would if's". He said to spend each moment enjoying what you have, making the best of each opportunity. Live life.
I guess It just really made sense. What good is looking forward to something if you don't enjoy every minute when it finally does come? Often I find that by the time we get to the thing that we were looking forward to, we've already moved on to the next "looking forward to" if you know what I mean.
So enjoy each moment. Don't say, "Aww man, I wish it was longer" Instead take that moment and say, "Wow, what a privilege it is to be here, or do this right now, today." And when It's over, God'll bring something else into your life.
Life is full of up's and down's. Enjoy the moment, enjoy the memory, but don't dwell on the negatives when it really is filled with positives... Take it, learn from it.