When you feel frightened, angry, or sad, reality contracts until whatever is upsetting you takes up the whole world—at least the one between your ears. Life seems like a vale of tears, the future looks bleak, and the only memories that come to mind are unpleasant. The best explanation for why bad feelings shrink your focus is that in a potentially ominous situation, homing in on and reacting to any trouble quickly is more important than taking your time to get the big picture.