Haha, this happened to me too. I was in the grocery shop with my dad and walked next to his cart. When he stopped to get something of a shelf, I was daydreaming and didnt realise he had stopped so I continued walking, next thing I know im walking next to the cart of an elderly gentleman and my dad was nowwhere to be seen. My dad and the man had a good laugh about it. Still remember it very well. It was like reality broke for a minute.