Benedict Cumberbatch is very good at what he does. 

But for reasons that will become apparent, he didn't think his 'f*cking' face was necessary when he auditioned for the role of Smaug the Dragon in The Hobbit films, and as such, ended up sending a hilariously bad (but good obviously seeing as he landed the role) tape to director Peter Jackson. It does however make for a very good anecdote.

Via YouTube