Self-doubt brings fear, such as the fear of failure, of the dark, of being out of control, of not being good enough. We fear loving because we doubt our ability to love and so fear rejection; we fear being generous because we doubt our capacity to generate more and fear we will not have enough. We fear sharing our thoughts or feelings for doubt that we will appear wrong or stupid. Doubt brings mistrust, which appears real, even though it may have no real substance. It arises when the ego is threatened or undermined. Such doubt creates worry, nervous disorders and even paranoia. It is the enemy of real happiness.