The best is the enemy of the good.

"La Bégueule" (Contes, 1772) | Note: translation of earlier traditional Italian Il meglio è nemico del bene, attested since 1603: Proverbi italiani (Italian Proverbs), by Orlando Pescetti (c. 1556 – c. 1624) (p. 30, p. 45) | Note: Voltaire cites this saying in his poem "La Bégueule" ("The prude woman") while ascribing it to an unnamed "Italian sage"; he also gives the saying (without attribution) in Italian (Il meglio è l'inimico del bene [note spelling difference: l'inimico instead of nemico for "[the] enemy") in the article "Art Dramatique" ("Dramatic Art", 1770) in the Dictionnaire philosophique

s: The perfect is the enemy of the good. The better is the enemy of the good.