“Rosie laughed in a not too reassuring way if you like sane laughter.”

“Scully nodded. Of course. It made sense. Complete sense. No question about it. Mulder was perfectly sane in telling her all this. And she was perfectly sane in listening to it and nodding and urging him to tell her more. It was the rest of the world that was-She doubled over as a wave of laughter hit her.Mulder looked at her and started laughing too. They stood there in the cemetery in the darkness and the drizzle, laughing their heads off.'You know we're crazy,' Scully finally said.'Of course we are,' Mulder gasped out.”

“The laughter of the world is merely loneliness pathetically trying to reassure itself.”

“If you're too serious to make life a laughing matter, then you seriously need to make laughter matter to you today and every day!”

“She laughed like she'd just invented laughter.​”

“Then he heard a wild, high-pitched cackling that made the hair stand up on the back of his neck. It wasn't sane, that laugh. In fact, it was the laughter of someone who never had more than a nodding acquaintance with sanity.”