(the) better is the enemy of (the) good

The demand, desire, or insistence for perfection decreases the chances of obtaining a good or favorable result in the end. I know you want your research paper to be great, but better is the enemy of good. At this rate you won't even finish it in time! As a manager, you have to realize both the potential and the limits of your employees. Push them when necessary, but keep in mind that the better is the enemy of the good. I tend to be a perfectionist, so "the better is the enemy of the good" has become like a mantra for me. Otherwise, I'd never finish anything.