R is a velocity of measure, defined as a reasonable speed of travel that is consistent with health, mental well-being, and not being more than, say, five minutes late. It is therefore clearly as almost infinite variable figure according to circumstances, since the first two factors vary not only with speed as an absolute, but also with awareness of the third factor. Unless handled with tranquility, this equation can result in considerable stress, ulcers, and even death.

Trillian had come to suspect that the main reason [Zaphood] had had such a wild and successful life was that he never really understood the significance of anything he did.

Will you stop counting!' snarled Zaphod. 'Yes,' said Ford Prefect, 'in three minutes and thirty-five seconds.

Many respectable physicists said that they weren't going to stand for this -- partly because it was a debasement of science, but mostly because they didn't get invited to those sort of parties.

So this is it," said Arthur, "We are going to die." "Yes," said Ford, "except... no! Wait a minute!" He suddenly lunged across the chamber at something behind Arthur's line of vision. "What's this switch?" he cried. "What? Where?" cried Arthur, twisting round. "No, I was only fooling," said Ford, "we are going to die after all.

Ah, this is obviously some strange usage of the word 'safe' that I wasn't previously aware of.

And then, one Thursday, nearly two thousand years after one man had been nailed to a tree for saying how great it would be to be nice to people for a change, a girl sitting on her own in a small café in Rickmansworth suddenly realized what it was that had been going wrong all this time, and she finally knew how the world could be made a good and happy place. This time it was right, it would work, and no one would have to get nailed to anything.