I was reading this book: Truth.
It’s about acting but was recommended as a good book to read for directing actors. It took me a couple days to wrap my head around the ideas the author presents, but now that I get it, I agree:

The character need is something so desperate that the character’s entire persona is built around protecting themselves from it. Failure in any arena unrelated to that need is bearable; the character can bounce back… but failing in that need would be devastation.

Need + persona = tragic flaw. The persona, built to protect, renders fulfillment of the need nigh-impossible.

When I first read it, I disagreed. After thinking on it for a few days and comparing it to the characters in Sweetpea (and myself).. s’truth

Check out the book if you like: http://amzn.to/s3OgFx