Fear

Fear is the physical and emotional response to dangerous or threatening situations that prepares the body to fight or flee the situation (you know, the old Fight-or-Flight Response). It causes a release of adrenaline into the body that heightens the senses and provides energy to the muscles in order for the person to react successfully to the situation or event. In our modern times we've all had the experience of being startled by something unexpected and feeling the adrenaline surge that went with it. In more primitive times this fear reaction could make the difference between life and death.