Dic: the best is the enemy of the good

Let the best be the enemy of the good.

If the desire for an unattainable perfection stops someone from choosing good possibilities, they let the best be the enemy of the good.

..... usingenglish.com

best is the enemy of the good

Prov. If you are too ambitious and try to make something better than you are capable of, you may ruin it.

• Bob: After I revise it a few more times, my novel will be the best ever written.
  Alan: I don't think you should revise it any more. Remember, the best is the enemy of the good.
• In fundraising as in other areas, the best is the enemy of the good. If you ask someone for a larger contribution than he can possibly give, he may give you nothing at all.

.... http://idioms.thefreedictionary.com/best+is+the+enemy+of+the+good

The original quote in French is "Le mieux est l'ennemi du bien.", from Voltaire's Dictionnaire Philosophique (1764)

• Literally translated as "The best is the enemy of good.",
• but is more commonly cited as "The perfect is the enemy of the good."

In other words, pursuing the "best" solution may end up doing less actual good than accepting a solution that, while not perfect, is effective. One could also infer that the best makes that which is good seem to be worth less than it is.

....www.famous-quotes.net