When I was a kid, and Monogram had just issued its 1/48 B-17 kit, I and my best friend both got the kit for Christmas.  We lived next door to each other, and so, we could compare notes very easily.

Two days after Christmas, he had his finished.  I was still painting and assembling the interior.

I asked him if he added the interior pieces and painted them, and he said no.  He said, "No one will ever see them."

He asked me if I was building the interior and I said yes.  He asked me why, and I said, "Because I know it's there."