Work for work's sake

Gita says not to think of the result and just work for work's sake. Its difficult to achieve that state of mind. But what if we do achieve it. And then due to some other reason are unable to achieve what we wished. Just a single wish in life. And we aren't granted it. Or maybe we're feeling lost before we have actually? And the real reward is really hidden...and on its way, bigger than we asked for?