Character flaws. We all have them, and most of us struggle to overcome and control them. However, they are also a badge of our humanity. It gives us humility to admit our imperfections. We take comfort in the fact that others also struggle. We sympathize and empathize with their struggles because it allows us to accept our own imperfections. It gives us courage to continue to strive for perfection knowing that others are also working against the same odds.
In literature, character flaws give a character credibility and likability. Since humans are inherently imperfect, we can't identify with characters who have no flaws. But character flaws by themselves are not enough. Characters must have some redeeming quality that makes us hope, against all odds, that that even the worst villain will recognize the error of his ways and repent. When he doesn't, we can accept whatever fate befalls him.
As in real life, some characters suffer from a tragic flaw. This flaw is so overpowering that no matter how hard they struggle, they are unable to overcome it. It becomes inevitable that this flaw is stronger than the individual and eventually they succumb to it. We feel sad when this happens, but we also feel vindicated. The character's failure to persevere sends the message that we must continue to struggle against these flaws or perish.
While some character flaws are off-putting, others may actually provide comfort and draw people in. This is the power behind support groups. Knowing that one is not alone in his or her suffering and that others have had similar experiences can provide one with the strength and courage to continue the struggle. Even fictional characters can provide insight and understanding during one's time of need. As characters struggle to overcome their fictional difficulties, it can provide direction to those who struggle in real life.
If literature is indeed the mirror we hold up to life, then our characters should also reflect the complexity of human nature, including all the burrs and bristles.