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.

Common Names:

Name	Pronounced	Usage
Mellony	-	English (Rare)
Fang	-	Chinese
Tomislava	-	Croatian, Serbian, Medieval Slavic
Nemo	NEE-mo (English)	Literature
Darshana	-	Indian, Marathi
Herodes	-	Ancient Greek, Biblical Greek, Biblical Latin