Missing when you dont have, lost when you got the chance

When you don't have, you are missing it very much.
But when you got the chance, but you never know what should you do in the next.
Isn't it sad enough?

Writing a blog just like writing a diary.
Drop down all the feeling I have before and view back when I like too, the feeling is so great. ;op It sounds to remind me what I used to be in the past.