be (one's) own worst enemy(redirected from are their own worst enemy)
be (one's) own worst enemy
To do things that complicate one's life and/or keep one from success; to be self-destructive or self-sabotaging. Of course Tommy started skipping school again—he's his own worst enemy. She always sabotages a relationship when it's going really well because she's her own worst enemy.
be your own worst enemyact contrary to your own interests; be self-destructive.
1993 Richard Lowe & William Shaw Travellers We convinced ourselves that everything was against us but the truth was we were probably our own worst enemies.