Difference between Phobia and Mania

Do you know the difference between phobia and mania? Phobia is a condition where there is an undue and irrational fear of some thing; where as mania an aggressive desire towards something. For example agrophobia is the fear of being in open spaces and agromania is the craving to be in open spaces. Both phobia and mania are manifestations of defense mechanisms we use to handle situations that we are incapable of handling in a healthy way. Fear in general is not a psychological pathology and it is actually a self preservation mechanism which all of us should possess; if we do not fear of flames we would walk into fire and burn ourselves alive. When this fear becomes our preoccupation then it becomes difficult to lead a normal life; our interaction with the external world gets impeded. Similarly, desire in its essence is not a psychological pathology, but when it interferes with our normal day-to-day activities, then it becomes a pathological condition.