The principal cause of suffering is

The principal cause of suffering is craving. Once craving is eliminated, much suffering will be eliminated. Still more suffering will be eliminated once ignorance is eliminated. Both craving and ignorance are equally powerful defilements that cause suffering.

~ Bhante Henepola Gunaratana

the principal cause of suffering is
 
"One day I will find the right words, and they will be simple." Jack Kerouac