There's this scene in "The Night of the Hunter" when the kids are downstairs, and you have the feeling that they're both in a room and at the same time it looks remote. And you wonder, How can you give the effect of both "inside" and "outside" at the same time. And you realize, by watching it many times, that around the scene there's this black edging.
The things you need in life are those that will help you to fulfill your dominant purpose. Things you may want but not need may lead you aside from that purpose. It is only by making everything serve your main objective that success is attained.