because eventually everyone gets an exit.
This planet has – or rather had – a problem, which was this: most of the people living on it were unhappy for pretty much most of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.
One of the things he had always found hardest to understand about human beings was their habit of continually stating and repeating the very very obvious, as in
It's a nice day, or
You're very tall, or
Oh dear you seem to have fallen down a thirty-foot well, are you all right? At first he had formed a theory to account for this strange behaviour. If human beings don't keep exercising their lips, he thought, their mouths probably seize up. After a few months' consideration and observation he abandoned this theory in favour of a new one. If they don't keep on exercising their lips, he thought, their brains start working.
It is an important and popular fact that things are not always what they seem. For instance, on 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.