One Pack. No Turning Back.
As if my OCD wasn't already bad enough as a kid, here was a card perfectly designed to indulge the most obsessive of baseball fans, with its mini-print and miniscule check boxes that one could use to track their collection as they bought wax pack after wax pack. Most people probably recognized the absurdity of this card and didn't give it a second look, but back in the pre-Internet 1980s, how else would you know all the players' names who were in a given card set? The checklist was an indispensable resource to baseball nerds like me, a way to feel in control of your collection and to identify the gaps.