The birds are the eyes of heaven, and the flies are the spies of hell.
Even heaven would become hell if you were alone in it, or away from a loved one. And even if you were with your loved one, but in hell, eventually you would cry to have you and your loved one together in heaven. So to create your own heaven on earth, make sure you and your loved one are in a place you both LOVE, because what could be heaven for one, could be hell for the other.