A Scrap of Conversation

Two days ago, as my partner and I were about to buy a jar of honey for my father, a saleslady tried to offer her advice.

Saleslady: Mbak, why don't you buy the larger jar? (pointing at a jar containing at least a gallon of honey)
Me: Why should I? (holding a much smaller jar)
Saleslady: You see, this large jar contains more honey than the jar that you're holding.
Me: Yeah... of course.