This characteristic of loneliness makes it reasonable how Snape can execute his mission as a double spy so smoothly. Because there is no one who can completely understand Snape and share everything with him, Snape makes every decision himself and thus no one can really know what exactly is in his mind. He has been always misunderstood until he was killed by Voldemort and saved everybody in the end; also, he never got a chance to express his love about Lily even at the last minute of his life. His loneliness makes him a more tragic character and justifies his every deed.