Allyn Gibson wrote:
Perhaps the core of the story that Moffat has carried around for years went like this. Let's suppose there's a Doctor who's tired and weary and doesn't want to go on any more. He's ready to give up on life. And then, like Clarence in It's a Wonderful Life, another Doctor, a future Doctor no less, shows up and tells him that he shouldn't feel so bad. There's so much fun to be had in the universe. There are awesome things to do, fantastic places to see. The Doctor really has made a difference.
Funnily enough there is a character called Clarence in the Finale. He even gets the lead role in the "Prequel".