This a nice topic to think about... as I do agree that every moment counts and we should live life to the fullest, but it is not always easy just to be conscious about that. Let's say, if we go through some hard time or illness, we don't really think about how positive is that (in that moment). I know that I just want the pain to end. Later I do realize how grateful I am to be again well :)
Though in general, I think I am trying to find in almost everyone a positive thing to highlight ;)