I didn’t know where to find the notecards. With the open season on school supplies officially over, all of the spiral notebooks and colored pencils had drifted from their temporary home in a designated corner of the store back into the relative anonymity of the office supply section. I paced in front of the shelves, stymied, when I heard a loud crash. Maybe it wasn’t as loud as it seemed, but in the 10 a.m., weekday quiet of the store, it sounded that way. The noise was unmistakable, though: the sound of two shopping carts running into one another at speed. I hurried to the end of the aisle to find a white-haired woman in her late 60s pushing her cart down the aisle…