Maybe it's just another way to say that... sometimes, people -- humans... sometimes we're selfish, even when we pretend we aren't. Even if someone is doing something for someone else, maybe they're only doing it for herself. [Certainly she feels that way about herself. She's... so selfish, in the end.]
[Rattles her jar again, shrugging.] Maybe that's why sometimes this place will take any of the candy as payment.