At the Supermarket

I was at the supermarket, looping my way up and back down the aisles. As usual I was seeing the same people over and over as we leapfrogged (or should that be leaptfrog?) each other, picking up what was on our lists.
Rounding the end of lane I came across an older lady. Well if she was your mother you would probably still remember her as young but as a stranger she was middle aged. I had seen her in the last aisle with her husband when he'd been pushing the trolley.
Just as I was stopping to buy biscuits, the husband arrived around the corner with the trolley. His wife looked at him in surprise. "Whose trolley is that?" she asked, looking down at the one she had.
He tried to explain but in the end just laughed turned the trolley around and took it back to the previous lane. I don't know if he just abandoned it or maybe there was another shopper holding a can of something looking around for their trolley that had mysteriously glided off.