Shoot Oneself In The Foot Meaning

(idiomatic) To act against one's own interests; to unintentionally behave self-destructively.

Example: 1982 April, “Reagan shoots from the lip‎”, Black Enterprise, volume 12, page 16:
  but as President he frequently shoots himself in the foot. Some of his erroneous public statements are dillies.
2007, Paul Collier, The bottom billion: why the poorest countries are failing and what can be done about it, page 85:
  The countries that stopped shooting themselves in the foot were able to break into new export markets
2009 August, SPIN‎, volume 25, page 62:
  "I've always been the guy who shoots himself in the foot and squanders every opportunity," he says. "Now it's like, 'Do I throw it all away — or just try?'"