Three pages in, he felt his chest move, and realized to his astonishment that he was laughing. By the end of Chapter One, he wanted to know what happened next. He wasn't halfway through when the first tear fell.
He had lost everything: his family, his conscience, his family, his purpose. But not his literacy. People would always write more books. That was reason enough to live.
*
Also:
"What are you, crazy?"
"It's a possibility I haven't ruled out yet," said Zaphod quietly. "I only know as much about myself as my mind can work out under its current conditions, and its current conditions are not good."