The author is definitely full of quirks.
What Stephen King novel isn't though? You can tell that his characters' attributes are partially based off of his attitude or his sense of humor. With having read this book, it is made more clear that King puts his quirk into every manuscript he has ever written.
King does not shy away from the sarcastic one-liners that are responsible for making us laugh and adding a bit of humanity to heavy situations in his novels;
On Writing is, quite frankly, chock full of them. When he is either relaying some small part of his life
in the autobiography sections of the book, or suggesting some prose to use for writing, King cleverly add his two-sense in.