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.

"I'd far rather be happy than right any day." Slartibartfast

Marvin: "I am at a rough estimate thirty billion times more intelligent than you. Let me give you an example. Think of a number, any number."
Zem: "Er, five."
Marvin: "Wrong. You see?"

"If there's anything more important than my ego around, I want it caught and shot now."

"Time is an illusion. Lunchtime doubly so."

"You guys are so unhip it's a wonder your bums don't fall off."

"My capacity for happiness," he added, "you could fit into a matchbox without taking out the matches first"

Arthur: "Marvin, any ideas?"
Marvin: "I have a million ideas. They all point to certain death."

"What's up?" [asked Ford.]
"I don't know," said Marvin, "I've never been there."

"Six pints of bitter," said Ford Prefect to the barman of the Horse and Groom. "And quickly please, the world's about to end."

"I've seen it. It's rubbish." About a Magrathean sunset that Arthur finds magnificent.

In those days spirits were brave, the stakes were high, men were real men, women were real women, and small furry creatures from Alpha Centauri were real small furry creatures from Alpha Centauri.

"Ford," he said, "you're turning into a penguin. Stop it."

So long, and thanks for all the fish. Final message from the Dolphins, as they escape just prior to Earth's destruction.

"Have you any idea how much damage that bulldozer would suffer if I just let it roll straight over you?" said Mr. Prosser. "How much?" asked Arthur. "None at all," Mr. Prosser replied.

'Yet Unnamed Man': "Beeblebrox, over here!"
"No," called Zaphod. "Beeblebrox over here! Who are you?"
"A friend!" Shouted back the man. He ran toward Zaphod.
"Oh yeah?" said Zaphod. "Anyone's friend in particular, or just generally well-disposed to people?"

Ford, there is an infinite number of monkeys outside, who wants to talk to us about this script for Hamlet they have worked out.

Arthur: "Ford, I think I'm a sofa."
Ford: "I know how you feel."

"The mere thought," growled Mr Prosser, "hadn't even begun to speculate," he continued, settling himself back, "about the merest possibility of crossing my mind."

"Not that anyone cares what I say, but the Restaurant is on the other end of the universe"

"[Trillian] is one of the least benightedly unintelligent life forms it has been my profound lack of pleasure not to be able to avoid meeting."

"Here I am, brain the size of a planet and they ask me to take you down to the bridge. Call that job satisfaction? 'Cos I don't."

"Who said anything about panicking?" snapped Arthur. "This is still just the culture shock. You wait till I've settled down into the situation and found my bearings. Then I'll start panicking!"

"How do you feel?" he [Ford Prefect] asked.
"Like a military academy," said Arthur, "bits of me keep on passing out."