The Difference Between a Cat and a Comma

(This post was inspired by a conversation at the dinner table at which we discussed whether or not I could be hired by the FP Gal's school district to teach this distinction.)

What is the difference between a cat and a comma?

• If you put a dot above a cat they don't become a semi-colon.
• A comma is usually found on a keyboard. A cat is only sometimes found there.
• Cats use a litter box. No one knows where commas go to the bathroom.
• Cats are always grammatical.
• No one is allergic to commas.
• A serial comma is controversial. A serial cat is...apparently just one of a series of cats.