Improvement makes strait roads, but the crooked roads without Improvement, are roads of Genius.
 William Blake, The Marriage of Heaven and Hell (1790). copy citation

Context

“As the air to a bird or the sea to a fish, so is contempt to the contemptible. The crow wish'd every thing was black, the owl, that every thing was white. Exuberance is Beauty. If the lion was advised by the fox. he would be cunning. Improvement makes strait roads, but the crooked roads without Improvement, are roads of Genius. Sooner murder an infant in its cradle than nurse unacted desires Where man is not nature is barren. Truth can never be told so as to be understood, and not be believ'd. Enough! or Too much The ancient Poets animated all sensible objects with Gods or Geniuses, calling them by the names and adorning them with the properties of woods, rivers, mountains, lakes, cities, nations, and whatever their enlarged & numerous senses could perceive.” source