own worst enemy, to be one's

own worst enemy, to be one's

To be the major source of one’s own difficulties. The Greek philosopher Anacharsis (ca. 550 b.c.) already was stating this idea: “What is man’s chief enemy? Each is his own.” Cicero said it of Julius Caesar (Ad Atticum, 49 b.c.). In more recent times, cartoonist Walt Kelly expressed the same thought through his main character, Pogo: “We have met the enemy, and they is us.”
See also: own, worst