Van didn’t enjoy shopping, generally. Van enjoyed mathematics, tech hardware, cool sci-fi movies, his wife’s company, and bowling. However, shopping had one great advantage for Van. Shopping made Van stop thinking about Nash equilibria and latency functions. Van had been thinking about these two computer-science issues for three months, seriously. Then for two weeks very seriously, and then for the last six days very, very seriously. So seriously that even Dottie became invisible to him. So seriously that sometimes Van had trouble walking.