Человек сам себе враг

Some men act in such a way that they cause harm to themselves. See Не было у бабы хлопот, купила баба порося (H)

Cf: Beware of no man more than thyself (Br.). Each man makes his own shipwreck (Am.). Every man carries an enemy in his own bosom (Br.). Every man is his own worst enemy (Am., Br.). Evil is brought on by oneself (Am.). an only from himself can suffer wrong (Am.). A man's best friend and worst enemy is himself (Am.). None is hurt (offended) but by himself (Br.). You dig your grave with your own hands (Am.)