Anxiety is a perfectly normal experience that everyone has now and again. It can be a feeling like any other that comes and goes when you are faced with something like a new job or making an important decision in your personal life. However, anxiety disorders are different. When anxiety is chronic and interferes with your day-to-day life, it's more than a temporary, passing feeling. Anxiety disorders are serious mental illnesses that can leave someone unable to go about their normal life.