If one bad thing befell me, I immediately linked it to every bad thing that had happened in the last week or might happen in the coming week. And when I became sad, I was prone to wallow in grief, piling up my woes and sprawling on them like a dragon on a hoard.
"I don't want anything else bad to happen," she whispered, her voice choked with tears. "I'm so sick to death of bad things happening, of seeing bad things that happened in the past! And I'm guilty of so many things. I'm sorry that I killed Mrs. Matthias and wrecked her stupid greenhouse back in the Eighties and I'm sorry I left you here alone while I went around the world." "I wasn't alone though, I knew you were doing what you wanted to do and that you were still alive, so I wasn't really alone, I knew you were still there somewhere," Alecto told her. His damaged smile and downcast, sorrowful eyes were draped in the shadow of the night, saving Mandy the trouble of seeing."
Given their current circumstances, things would have to be very bad indeed for Tilly to think the situation had gotten worse. Sure, they were all trapped in orbit around an alien space station that periodically changed the rules of physics and had killed a bunch of them, but now they'd decided to start shooting each other too. Yes, very bad.
In some ways, it was far easier to be bad than good. When you're bad, you don't care what happens to anyone other than yourself. When you're trying to do god, you have to worry about everyone.