"Describe worrying," he went on.Neal Stephenson, Anathem
"Pretend I'm someone who has never worried. I'm mystified. It don't get it. Tell me how to worry."
"Well...I guess the first step is to envision a sequence of events as they might play out in the future."
"But I do that all the time. And yet I don't worry."
"It is a sequence of events with a bad end."
"So, you're worried that a pink dragon will fly over the concent and fart nerve gas on us?"