It can affect a person's mood and attitude in multiple ways. Stress can make a person feel anxious or exhibit symptoms of anxiety. This is particularly serious in people with generalized anxiety disorder (GAD); GAD causes people to worry about any little thing in life. Another symptom of stress is irritability or hostility/anger. So even though the subject may be a generally carefree and laid-back person, stress may cause them to have an affected fight or flight response. This causes them to perceive even small things as a threat which can lead to exaggerated responses to stressors. Stress also manifests itself in thoughts. These thoughts may include self-criticism, difficulty concentrating, forgetfulness and general mental disturbances.