Great effort in the wrong place

It is said that; once a man who lost his keys somewhere and took him looking and asking people about it !!
Does anyone saw my keys ..!
So, some people surround him asked .. Do you lost it here ... he said, no i lost it in another place.. then one of they asked him ..and Why you're looking for it here ..!
He said, because the light here bright and I've a clear vision to be sure it's not here.
What i meant is .. If great effort organized in the wrong place .. it does not affect the outcome