Achilles heel...

Ever wonder where this one came from? One weak spot in an otherwise strong character or position---"Public speaking is his Achilles heel"--- Greek mythology - Thetis, leader of the sea nymphs wanted to make sure her infant would be impervious to battle as an adult, so she dipped him in the river Styx, whose water was believed to confer invulnerability. One heel remained dry because she held him by that heel to dip him. Achilles died as a result of an arrow wound in the heel which remained unprotected.