Certain angles create certain effects. The position of the camera and the way that we as an audience literally see what's on screen. 

In this shot from The Road Warrior, Miller uses a downward angle from the tree's perspective to give the scene tension. It also adds a voyeur aspect to the shot as it seemingly comes from the perspective of someone watching Max walk into a trap rather than the objective medium shot. 

This is what is typically referred to as a "dutch angle" which is when the camera is tilted on an axis. Miller uses it here to show Max's mental state. He is uncomfortable here and the dutch angle shows a bizarre environment that Max does not entirely understand just yet.