Maybe the perfect paragraph

As the president stepped up to 10 Downing Street, he leant over, made eye contact, said something courteous, and shook the hand of the police officer standing guard. There's always a police officer there; he is a tourist logo in his ridiculous helmet. He tells you that this is London, and the late 19th century. No one has ever shaken the hand of the policeman before, and like everyone else who has his palm touched by Barack Obama, he was visibly transported and briefly forgot himself. He offered the hand to Gordon Brown, the prime minister, who was scuttling behind.

What is a paragraph, you ask? I give you this, written by A. A. Gill, a contributing writer for Vanity Fair and The Sunday Times of London. 

He starts with a keen observation passed to us in story form. We can see it; we get where this is going. But before we can settle in, right there in the second sentence, the observer intrudes and the story is interrupted. "There's always a police officer there..." A simple statement, and we get that too. Then in the very same sentence, a surprise: the tourist slam and the helmet jab--and we learn that the observer is not merely of the objective kind. 

A follow-on sentence extends the fun, which turns out to be a set-up for: "No one has ever shaken the hand of the policeman before..." With this we have the twin pillars on which the paragraph is built: There is always a police officer there/no one has ever shaken his hand. Always/never. 

Suddenly it's clear that the swipes against the officer's appearance were structural--they provided the proper spacing between the two load-bearing statements. But we're not done yet. We're told something that we can only take on faith: the policeman was transported and briefly forgot himself. Excellent writing has prepared us to believe this assertion that only the policeman himself could have actually experienced. 

We leave the paragraph the same way we entered it--the story rejoined: policeman offers hand to prime minister. And if it's the attitudinal subplot you prefer, you're rewarded again: whereas we came in with the American president "stepping up" to 10 Downing Street, we go out with the British prime minister "scuttling behind" ... at the entrance to his own official residence and headquarters of Her Majesty's Government. 

(whence it came)