“The rule is: the word 'it's' (with apostrophe) stands for 'it is' or 'it has'. If the word does not stand for 'it is' or 'it has' then what you require is 'its'. This is extremely easy to grasp. Getting your itses mixed up is the greatest solecism in the world of punctuation. No matter that you have a PhD and have read all of Henry James twice. If you still persist in writing, 'Good food at it's best', you deserve to be struck by lightning, hacked up on the spot and buried in an unmarked grave.”

“No matter that you have a PhD and have read all of Henry James twice. If you still persist in writing, "Good food at it's best", you deserve to be struck by lightning, hacked up on the spot and buried in an unmarked grave.”

“If you still persist in writing, "Good food at it's best", you deserve to be struck by lightning, hacked up on the spot and buried in an unmarked grave.”

“The reason it's worth standing up for punctuation is not that it's an arbitrary system of notation known only to an over-sensitive elite who have attacks of the vapours when they see it misapplied. The reason to stand up for punctuation is that without it there is no reliable way of communicating meaning.”

“To those who care about punctuation, a sentence such as "Thank God its Friday" (without the apostrophe) rouses feelings not only of despair but of violence. The confusion of the possessive "its" (no apostrophe) with the contractive "it's" (with apostrophe) is an unequivocal signal of illiteracy and sets off a Pavlovian "kill" response in the average stickler.”

“If this satanic sprinkling of redundant apostrophes causes no little gasp of horror or quickening of the pulse, you should probably put down this book. By all means congratulate yourself that you are not a pedant or even a stickler; that you are happily equipped to live in a world of plummeting punctuation standards; but just don't bother to go any further.”

“Thurber was asked by a correspondent: "Why did you have a comma in the sentence, 'After dinner, the men went into the living-room'?" And his answer was probably one of the loveliest things ever said about punctuation. "This particular comma," Thurber explained, "was Ross's way of giving the men time to push back their chairs and stand up.”