Perfectionism is enemy to productivity. In setting goals, we should choose ones that stretch us but that still reside in the realm of possibility. Having goals that are too lofty will demotivate us because we won’t really believe we can achieve them (with reason), and can harm our progress. Instead, setting goals that are realistic will give us more incentive to pursue them, and allow us to enjoy the success of completing them.
Source: learn.filtered.com