I remember, waaaaaay back in grade school, being discouraged from ending a story with the words "The End". Why?! Unless I'm planning on writing a sequel, those two words give perfect closure to a story. "What happens next?" nothing! It's The End.
We were told that it's "not professional" – by the same people that taught us not to start a sentence with the words "and" or "but". Ever. And you know what? I hate that "rule" too. But, I do it all the time anyway. And it's accepted. It's acceptable.
I recently read the book "The Road", and was frustrated at first by the lack of punctuation. The dialogue was mixed in with the story with no quotation marks. A couple of times I had to reread a section of dialogue to figure out whether the even or odd lines of dialogue were "the boy" or "the man", as their was no other indication.
Did Cormac McCarthy miss these "rules", or did he just say "fuck it all – I'm going to write the way I want"? Granted, even Cormac didn't end the book with "The End", but he could have, and they still would have made a movie out of it.