Some days are just bad days, that's all. You have to experience sadness to know happiness, and I remind myself that not every day is going to be a good day, that's just the way it is!
Dita Von Teese

Sadness is but a wall between two gardens.
Khalil Gibran

Make the most of your regrets; never smother your sorrow, but tend and cherish it till it comes to have a separate and integral interest. To regret deeply is to live afresh.
Henry David Thoreau

The tragedy of life is in what dies inside a man while he lives - the death of genuine feeling, the death of inspired response, the awareness that makes it possible to feel the pain or the glory of other men in yourself.

You left and I cried tears of blood. My sorrow grows. Its not just that You left. But when You left my eyes went with You. Now, how will I cry?
Rumi

Your pain is the breaking of the shell that encloses your understanding.
Khalil Gibran

Isn't it sad to go to your grave without ever wondering why you were born? Who, with such a thought, would not spring from bed, eager to resume discovering the world and rejoicing to be part of it?
Richard Dawkins

If we could read the secret history of our enemies we should find in each man's life sorrow and suffering enough to disarm all hostility.
Henry Wadsworth Longfellow

A lot of country music is sad. I think most art comes out of poverty and hard times. It applies to music. Three chords and the truth - that's what a country song is. There is a lot of heartache in the world.
Willie Nelson

The closing of a door can bring blessed privacy and comfort - the opening, terror. Conversely, the closing of a door can be a sad and final thing - the opening a wonderfully joyous moment.
Andy Rooney

I had rather have a fool to make me merry than experience to make me sad and to travel for it too!
William Shakespeare

There's a rule of writing: if everything is funny, nothing is funny; if everything is sad, nothing is sad. You want that contrast.
J. Michael Straczynski