Veronica8
Yep. Very much agree. How to face your inner antagonist is usually the difference between a 'strong' and a 'weak' character. That said you could have fantastically interesting weak characters in a story, but unless it's some kind of 'literary' fiction weak characters seldom make for good main characters.
They can be really well written, but it's kind of depressing reading about someone walking down the road to self-destruction. Oedipus, here we go for for some laughs, or not...
Now, weak-willed antagonists, however. Those can be really, really, really scary. You can feel the resentment oozing when you read, and as they don't really change (since they won't face those inner demons) you can have your leads helping them towards redemption -- and the reader knows there's backstabbing coming sooner or later.