There's an old German saying, originating in a 17th-century poem, that means “good thought, poor execution.” In the poem, a bear is assisting a human friend who's trying to sleep but being pestered by a fly on his nose. The bear throws a heavy stone at the fly, and well, splat. Translated literally from the German “jemandem einen Bärendienst erweisen”—it's "giving someone bear service."