To allow the demand, desire, or insistence for perfection decrease the chances of obtaining a good or favorable result in the end. (Usually used in the negative as an imperative.) I know you want your research paper to be great, but don't let perfect be the enemy of good, or you won't even finish it in time! As a manager, you have to realize both the potential and the limits of your employees, so be sure not to let the perfect be the enemy of the good.