I don't agree that anxiety is an mental illness, either. But I hate the too anxious feeling, which makes me perform inadequately, lose appetite, not sleep well, insomnia, irritable. I think feeling too anxious is indeed a distress, but should not be viewed as a mental illness, but as a reflection of the high impact level that event causing anxiety brings and thus the urgency of dealing with that event. Adequate anxiety can goad one progress toward her/his goal, but over anxiety would lead to the adverse effect. I think the human mood is the response to one's surrounding events and it sounds absurd to me that some medicine is devised to remove or change one's negative moods because in that way one doesn't really need to solve the problems which trouble them nor needing certain enjoyable things to feel happy but just take some medicine which can remove their anxiety or make them feel happy.