Human nature is generally tricky, sometimes odd and quite often hard to fathom. One of the more awesome ways of observing us mammals and our peculiar interest in valuable objects is the classic dollar-bill-on-a-string trick.
Surely you remember this one from your childhood: some joker attaches a string to the underside of a dollar bill and hides behind a corner. Then, when you reach down for it, the person yanks it away. But that’s so last century.