When good is never good enough

Perfectionism is a habit many translators and other freelancers seem to have. In their work they strive to deliver the best quality possible and even try to supersede that demand by doing even better. Although it is good to aim to deliver the best translation time after time, aiming for perfection can eventually derail work and leave the translator with an ever growing feeling of guilt for not having delivered the best translation and a great darkness of increasing workload. How can translators (and other freelancers) deal with perfectionism?