It plausible that either she was too dumb to understand or that she just didn't care.
We used to get birthday cake once a month to 'celebrate' all the birthdays that month, and as a leader, I always had to serve it. This lardarse would come up, and despite the fact that I had 4 of each flavor plated up, she'd point at one still in the cake and say "That one"...not please, not 'could I have that one', just "that one". You know on a boughten cake, how there's without fail at least one piece of cake with a decoration on it that has like a pound of frosting to the point that no one in their right mind could enjoy that much frosting, because you'd never taste the cake? Yep, that's the one she went for, every time. I used to call her weeble-wobble (in private, of course) because she was as big around as she was tall, and I used to imagine someone running into her, and her just rocking back and forth like a weeble-wobble.