Seneca on Success

"Pronounce yourself happy only when all your satisfactions are begotten of reason, and when, having surveyed what men struggle for, pray for, watch over, you find nothing to desire let alone prefer. I give you a rule of thumb to assess yourself and ascertain your perfection: You will come into possession when you understand that the 'successful' are least successful. Farewell."

Letter 124, "Reason and the True Good," Seneca.