A common metaphor used to critize someone’s inquiry:
One night, a drunk man is searching on the ground under a streetlight. An officer approaches and asks “What are you looking for?”
“My keys.”
They look together for a while until the officer asks, “Are you sure you dropped your keys here?”
The man replies, “No, over there” and points to a dark patch far from the streetlight.
“Why in God’s name are you looking here, then?”
“Because there’s no light over there.”