This is a great point. I did bring up the relationship exercise in the post, but admittedly I didn't give it enough respect.

In college, my database teacher told us to design a database with at least 50 tables and 100 relationships by the end of the lecture. "It will be easier than you think", he said. And it was! And I thank him for that, because that lecture alone probably got me through more progress in product design discussions than anything else.