If anyone is unhappy, remember that his unhappiness is his own fault... Nothing else is the cause of anxiety or loss of tranquility except our own opinion.

Epictetus (50-135), Epictetus was a Greek Stoic philosopher. He was born a slave at Hierapolis, Phrygiaand lived in Rome until his banishment, when he went to Nicopolis in northwestern Greece for the rest of his life.