We can say "a little bit of anxiety" because it keeps people alert to everyday life, and is better prepared to drive the risk, mastery and accomplish the various tasks required during the day, and anxiety is a positive stimulant to adapt to reality and its requirements. For a long time, where anxiety becomes a positive motive to become a disorder that negatively affects the life of the person and disrupts, and even makes the nerves of the person tense and anxious