In The Royal Tenenbaums, Margot Tenenbaum (Gwyneth Paltrow)'s father, Royal, never let her forget growing up that she was adopted. So it's no wonder she falls in love with her brother Richie (Luke Wilson). After all, they aren't blood related. Their love story is actually really sweet, despite it being slightly incestuous. And you can't help but get teary eyed when Margot comforts Richie after he attempts suicide.
Line on Love
Margot: "I think we're just gonna have to be secretly in love with each other and leave it at that, Richie."