Why do you care?

Lukas' latest "thing" has been to ask me where I got something.

"Where did you get the pasta, Mommy?" "I got it at Ralphs."

"Where did you get the papaya, Mommy?" "I got it at Costco."

"Where did you get the parmesan cheese, Mommy?" "I got it at Ralphs."

"What aisle was the cheese in, Mommy?" Ok, I had to think about it. "I think it was in the aisle with the pasta."

Why does he care? Someone, please tell me!