Dear Mister Language Person: What is the purpose of the apostrophe?

Answer: The apostrophe is used mainly in hand-lettered small business signs
to alert the reader than an "S" is coming up at the end of a word, as in:
WE DO NOT EXCEPT PERSONAL CHECK'S, or: NOT RESPONSIBLE FOR ANY ITEM'S.
Another important grammar concept to bear in mind when creating hand- lettered
small-business signs is that you should put quotation marks around random
words for decoration, as in "TRY" OUR HOT DOG'S, or even TRY "OUR" HOT DOG'S.
-- Dave Barry, "Tips for Writer's"