WintersTale
One of the biggest regrets of my life happened when I was 20, about 10 years ago.
I was working my job as a cashier, and a father and his son came through the line. The little boy's head was down, and the man was very unpleasant. The man started to walk off, but the boy came towards me, and whispered "help me." Then they left before it registered that this was probably an abusive situation.
I was too late to get the license plate, but I've always regretted that. I had the chance to help a child, against a possibly abusive father, and I missed it. I hope he's okay wherever he is.