"Never to suffer would never to have been blessed." 
-Edgar Allen Poe

"Remembering a wrong is like carrying a burden on the mind." 
-Gautama Buddha

"Man stands in his own shadow and wonders why it's dark." 

-Zen Proverb

"We should feel sorrow, but not sink under its oppression."
-Confucius

"You cannot prevent the bird of sorrow flying over your head, but you can prevent it from nesting in your hair." 
-Chinese Proverb