It's an old economists' joke. A person out walking at night comes across a man scrabbling on the floor under a lamppost. The man on the floor says he lost his keys. When asked when he dropped them he then replies, "Oh, I dropped them over there, but the light's better here."
It's an apt metaphor for how, if we're really honest with ourselves, sometimes we find ourselves working, or searching, or staying in the places where we find it easier rather than the places where we know we ought to be.