Emotions evolved as a way to help sufficiently respond to threats in the environment, or potential gains in the environment. We involve these emotions to help us do that and they can be an aid but also undermine our ability to think clearly. If you are hungry on your way to where you are going, so you're going to a restaurant that suddenly disappears, you won't feel the hunger. This is because this fierce adjust the parameters around which your brain is focusing. Len site's really interesting research did about the ways the emotion of disgust can screw with your decision making.