You can't see the wood for the trees
What's the meaning of the phrase 'You can't see the wood for the trees'?
By focussing on detail you lose perspective and miss what is important.
What's the origin of the phrase 'You can't see the wood for the trees'?
This proverbial saying is first found in John Heywood's 1546 glossary A dialogue conteinyng the nomber in effect of all the prouerbes in the englishe tongue:
An olde saied sawe, itche and ease, can no man please.
Plentie is no deyntie [dainty]. ye see not your owne ease.
I see, ye can not see the wood for trees.
Heywood's meaning is that, by having so many good things, people can miss the fact that life as a whole is good. In more recent times people might be advised not to worry about detail when life in general is good by being told that their concerns are "First-world problems" or, in Australia, they might be told "Don't sweat the small stuff".
See also: the List of Proverbs.