The many, many short chapters in this book are transcripts from a British radio program called My Word! The authors would pick a famous phrase, song title, book title, etc. and make up a story, the final line of which would be that phrase, but altered in some ridiculous way.

For example:
Beware of Greeks bearing gifts becomes Beware of sheikhs sharing lifts.
You can't have your cake and eat it too becomes You can't advocate and eat at two.
The mass of men lead lives of quiet desperation becomes The massive men need wives of quiet respiration.
And so on.

Most of the stories are just silly, a few are a bit crude, but some are very, very funny — and all of them exist just to make some silly variation on the opening line.