Alright, so, my cat loves boxes. She likes to sleep on them, particularly if it's one I need. The other day I got some foods from Sams Club, and one of the things I got was a box of hot-fry chips. THE MOMENT I set the box down after bringing it home, she ran right over, and relaxed on top of the box. It was big enough for her to sleep on top of, and that's all she wanted.
For the next few days, any time I wanted to grab a bag of hot fries out of the box, she would be sleeping on it, so I'd think, "Meh, I'll just get one later. No need to wake her up." One day, I was craving a bag, and she wasn't on it this time, so I grabbed a sack, opened the box, and stuffed all the bags inside, and let her have the empty box, and she slept inside it for a bit.
Apparently since I don't need the box anymore, it's no longer interesting, so now she's chosen a new box. https://dl.dropboxusercontent.com/u/80990655/kittybox.jpg So it's only big enough for half her body at most, but maybe she thinks I need that one now more than the other, or maybe it's only a good idea if it's HER idea.