The author's husband had criticized her need to incorporate a $4.00 latte into her daily commute. My initial reaction was the daily latter could fall into Rubin's suggestion of "Indulge in a modest splurge" (p.174) However, Rosman's husband calculated that she was spending $1000/year on lattes. This moved the latte out of the modest splurge category and into the somewhat pricey passion category.
As I read the article, I realized that in addition to the drink, the whole Starbucks experience was important to the writer. It was, in a minor way, her equivalent of going to the mythical "Cheers" to buy a drink. Entering the Starbucks, being waited on, possibly even that caffeine jolt made up for her grueling morning commute. She wasn't spending money on the item but on the experience.