This shot in 'Greif' shows a husband and wife in a bright house, but the bright lights juxtapose the darkness and tree silhouette that surrounds them. This creates a sense that there is something wrong and that they are surrounded by their troubles.
Juxtaposition is a technique whereby a filmmaker uses two things that are very different. When placed together on screen or by editing the two things closely together, they amplify each part. Eg, The Devil is very evil and dark, and an angel is very good. If they were in the same shot, the juxtaposition between them makes each seem more evil and good.
Juxtaposition doesn't have to occur between two 'real' things, sometimes an emotion or mood juxtaposes with what is seen on screen.
This shot in 'Greif' shows the bleeding husband suddenly very calm and talking to his therapy group (its a surreal vision that cuts abruptly into the action), so his bloody clothes and calm juxtaposes with the violence and horror that the husband and wife are experiencing just prior to the vision.
The girlfriend in 'Smiles' suddenly and abruptly starts cutting herself - this juxtaposes to the almost comedic tone of the story up to this point. The juxtaposition works to enhance the sudden and awful action as it takes the audience by surprise.
In this scene from 'Stucco', the character is having an incredibly odd dream where she is lured towards a fleshy object protruding from the wall. The music used is both juxtaposing to the tone and ordinary actions in the story prior, but also contrasts with her action of kissing the weird phallus. This use puts the audience into a very awkward state of mind, and challenges them with what could possibly happen next.
Stepping into a hole she has made in the wall, the main character in 'Stucco' steps from her ordinary house (albeit an increasingly bizarre place) into this dark and empty void as she finally confronts her inner demons. The juxtaposition between ordinary and metaphorical/supernatural space transitions and enhances the characters feeling of fear, horror & helplessness.
The juxtaposition used in 'Terrible Things' of the main character coming inside from a post apocalyptic wasteland (Grey toned, gas mask, misty) to a house where she lights a fire (dark, warm firelight), creates an almost intimate tone as she converses with a dead body and shares the terrible things she has done.