can’t see the forest/wood(s) for the trees

Focusing on small details makes one overlook the large picture. John Heywood’s proverb collection in
1546 has it, “Ye cannot see the wood for the trees.” A modern twist was pro- vided by C. S. Lewis in a critique of William Golding’s novel, The Inheritors:
“All those little details you only notice in real life if you’ve got a high tem- perature.You couldn’t see the wood for the leaves.”