Doubt helps us become truer to ourselves.
When you doubt your religion, you start to listen to the points of view of those of other religions or those with no religions. You become closer to your enemies. Artificial divisions are diminished.
When you doubt your political stand, you start to pay attention to other political points of view. You become more empathetic to your enemies. Artificial barriers are diminished and dialogue and conciliation can be more possible.
When you doubt your current job, you will start looking for other places that can make better use of your talents and enthusiasm. Possibilities are opened. You become more connected to yourself and those you are meant to serve.
Doubt is an important part of a rich life because it is a space where we finally meet our true selves and those of others. This is especially true because we agree about what we want and disagree about metaphysics and epistemology