In Moliere's Tartuffe, one character with a flaw is Orgon. The wealthy man who "adopts" the impostor Tartuffe is naive and foolish. He judges Tartuffe's value based upon what the con man says and how holy he acts, but never looks for real evidence of Tartuffe's pious and Christian nature. Tartuffe puts on a great "act," but it is only that. Orgon never witnesses Tartuffe offering comfort or kindness to anyone—but he is too deluded to even notice.
This flaw prevents the family from being happy. Orgon arranges for Tartuffe to marry his daughter Mariane (even though he has promised her to another, and a man she loves at that). Orgon does not believe his son Damis when he says he witnessed Tartuffe attempting to seduce Elmire. He prevents Tartuffe from being thrown out of the house because Orgon is so blind. Orgon also prevents his wife from feeling that her husband supports her when he will not believe her report about Tartuffe's inappropriate advances.
Madame Pernelle is Orgon's mother. She is also blind to Tartuffe's flaws. Had she been more willing to examine Tartuffe's behavior more closely, she might have joined the others in convincing Orgon that his house guest was a fraud. However, she scolds everyone, tells them that Tartuffe is trying to correct their immoral behavior (which they really don't engage in), and prevents the family from reasoning with Orgon and arranging for Tartuffe to be exposed and thrown out "on his ear" when he first arrives.