If I were to make a presentation to a specific audience on Sir Walter Scott's famous statement from Marmion, "Oh what a tangled web we weave / When first we practice to deceive!" I would use Wuthering Heights and A Doll's House.
Emily Brontë's 1847 Wuthering Heights, filmed in 1939 by William Wyler, is a constant battle between Heathcliff (Rex Downing/Laurence Olivier) and Catherine (Sarita Wooton/Merle Oberon) from the beginning. Catherine is an extremely snobbish person that loves Heathcliff but wants him to become wealthy before she will marry or run off with him. Money is of great importance to her. She lies to Heathcliff and tells him she does not love him. This outrages him; he knows she loves him; but her interests go where the money is. Heathcliff runs off. While he is gone, Catherine gets married. Heathcliff comes back a wealthy man. As soon as he gets back, he goes to visit Catherine. From this point on, they continually lie to each other and all those around them. Heathcliff and Catherine do nothing but horrible things to hurt one another.
When Heathcliff pretends to fall in love with Catherine's sister-in-law (Geraldine Fitzgerald), Catherine tries to warn her, but she does not believe Catherine. After they marry, Heathcliff treats her as if she is not even there. He speaks only of Catherine. Catherine has made herself sick from all of the battling with Heathcliff. Catherine dies, and Heathcliff is there with her. Even then he curses her for ever leaving him. This type of deceiving only leads to more and more painful experiences for everyone.
Henrik Ibsen's 1879 A Doll's House, filmed twice in 1973 by Joseph Losey and Patrick Garland, respectively, is another film/literature combination that I would use. Nora (Jane Fonda/Claire Bloom) has to lie and hide things from her husband, Torvald (David Warner/Anthony Hopkins). Nora has to borrow money when Torvald is sick. She has never told him because he has never believed in borrowing money. She has had constantly hide money in order to pay off her loan. Torvald treats Nora as his "doll." She has been merely a child to him. She has been given rules and not allowed certain things, such as her beloved macaroons.
When Torvald introduces her to Krogstad (Edward Fox/Denholm Elliot), her secret money lender, she pretends to have never met the man. His job at stake now that Torvald is to take over the bank; Krogstad threatens Nora, saying he will tell Torvald everything if he loses his job. Nora does everything she can to keep him from losing his job, but Torvald will not listen and even becomes very angry with Nora for trying to tell him what to do. She continues to lie to him. When Torvald finds out the truth, he is outraged and forbids Nora to have anything to do with him or the children ever again.
One a lie begins, another lie has to take place to cover up the first lie, and the lying goes on and on until one is forever untrustworthy.