Great writers don't follow rules. They don't look up in a style book how to use a comma. They invent their own rules. Some don't even care about the standard subject-verb-object order of English if they can create a dramatic effect, as in by the grace of God go I. Here's an example of an exceptional writer, whose name has often appeared in this blog, who defies conventional punctuation rules:
One sees that most human beings are wretched, and, in one way or another, become wicked: because they are so wretched. And one's turning away, then, for what I have called the welcome table is dictated by some mysterious vow one scarcely knows one's taken—never allow oneself to fall so low. – from James Baldwin, No Name in the Street in Collected Essays (Library of America, p. 374)
Most writing teachers would suggest that a dash should replace the colon, and a colon should replace the dash. To which Baldwin would surely say, "I don't care what you suggest." Baldwin was a born rebel, a fierce social critic, an American treasure, a global original, and an extraordinary writer, among the many other reasons why his life and work have resurged nearly four decades after his work. He has been the subject of notable documentaries, biopics, biographies, and plays. (For my money, he has never receded into the shadows of world literature.)
Back to my point. Writing by the textbook requires us to use colons for announcements and dashes for emphasis. Baldwin seems to apply those rules in reverse. But why fuss over rules when you want people to focus on your ideas, not your understanding of grammatical edicts? Be on the lookout for rule breakers in your reading of masterful writers.
