"He that is without sin among you, let him first cast a stone at her"!
It is something that we do as kids once or twice; we believe that everything is ours, we don't really know what accompanies it or what does it mean, until a combination of things forms the right view of that in our minds.
I also did that once, and I remember that I felt as if I was the worst person in the world! : ) It was a quite similar incident, with my mother uncovering the "sin"!
Every time I went back to that grocery store, I felt that even the products on the shelves were looking at me suspiciously! Ha ha! I understand!