"It is always the false that makes you suffer, the false desires and fears, the false values and ideas, the false relationships between people. Abandon the false and you are free of pain; truth makes happy, truth liberates." 

-Nisargadatta Maharaj

"Millions of people have decided not to be sensitive. They have grown thick skins around themselves just to avoid being hurt by anybody. But it is at great cost. Nobody can hurt them, but nobody can make them happy either." 

-Osho

"If you want to be happy, be." 
-Leo Nikolayevich Tolstoy

"If you put your conditioned intellect to rest for a long time, suddenly it will be like the bottom fallin out of a bucket -- then you will naturally be happy and at peace."
-Yuanwu Keqin

"The seed of suffering in you may be strong, but don’t wait until you have no more suffering before allowing yourself to be happy."

-Thich Nhat Hanh