I would like to forward an argument for the quality of work from writers who second-guess the strength of their work fifteen times a day. Doubt may not be the most pleasant of drives but it is a form of motivation nonetheless. It is not without its pit falls however.
Doubt without desire leads to submission. When a creator doubts themselves, it is really no more than an opportunity to test their determination. It's easy to concede but much harder to fight through the pull of this famous insecurity and relocate your confidence... but those that do... those that doubt themselves continually but find the drive to remember why they believe in their work, should never be doubted themselves. For it is in these people that we find the most heartfelt and detailed works. The silent self-defacing voice they hear simultaneously engages inspiration and originality in the most wonderful of ways.
So if you're like me and resort too quickly to doubt... try and remember that it is both a curse and a GIFT!