Had Scarlet been mean as sin itself, and Rhett lilly white, we would have been bored in minutes. But Margaret Mitchell did not allow this. She made us like Scarlet despite her bad qualities, she had us rooting for her in the end. And wishing we could talk some sense into Rhett too. Never look for the perfect to begin your story with.
Internal conflict comes from the characters own makeup.
Internal conflict is your character and why they react to certain situations the way they do. It is also the basis for characterization. In my manuscript Wandering Heart I made Angela, my heroine jealous, and made her come to grips with this emotion. In the end she was more real because she acted upon this emotion. Emotion and characters go together.