Survivor's Guilt
The day she had first heard about the ultimate fate of the cat, she refused to believe it. There was no way anyone could do something like that to the adorable Kyo-kun.
Then she thought about Rin-chan's parents. And how Momiji-chan had been abandoned. And how Haru-chan hated everyone.
And she didn't know what they had done to Yun-chan, but there had to be a reason he never talked to anyone.
Shortly afterwards, Kagura's parents realized she was missing. Hours later, when they asked her why she had been hiding in a dark closet, she was unable to explain why.
Author's note: This was written for a "Black Room" challenge from Tabbyprincess. I got to thinking about Kagura, and how it's likely that she might harbor feelings of guilt being in her situation: her parents, it is noted in the series and in the author's notes, are among the kindest of all the cursed Sohmas, and unlike almost all the others, she has no major psychological traumas (that we know about, that is). And considering how guilty she felt for treating Kyo condescendingly, it's quite possible she might also feel guilt for having a happy life, considering how many unhappy people surround her.
Sorry for being all serious. I'll try to make the next one funny.