Another interesting anecdote. In the version of the story published in The New Yorker, Ennis asks Jack, "You do it with other guys, Jack?" And Jack says, "Shit no." But in the book version, AP changed it to "You do it with other guys? Jack?" THe change in punctuation shows that Jack didn't answer, at least not right away, thus communicating that he had been riding other bulls, not rolling his own.
This reminds me about the mystery of the placement of commas in Hamlet, since we do not know whether Shakespere wrote, "To be or not to be, that is the question" or "To be or not, to be, that is the question" which can be interpreted a different way.