What's so unpleasant about being drunk?"
"Ask a glass of water!

It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.

The ships hung in the sky in much the same way that bricks don't.

For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much—the wheel, New York, wars and so on—whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man—for precisely the same reasons.

The hotel shop only had two decent books, and I'd written both of them

The waiter approached.
'Would you like to see the menu?' he said. 'Or would you like to meet the Dish of the Day?'
'Huh?' said Ford.
'Huh?' said Arthur.
'Huh?' said Trillian.
'That’s cool,' said Zaphod. 'We'll meet the meat.