One time I was in a long line at the post office. An elderly woman couldn't pay her post office box bill. She was really upset about it but there wasn't anything the clerk could do. When it was my turn I told the clerk I wanted to pay for the lady's p.o. box and to call her and let her know the clerk made a mistake and that the box was in fact paid up for the next 6 months. Later I kicked myself for not paying for the full year but I didn't know who the lady was or her box number so couldn't. The clerk started to cry when I paid for it. I often think of that lady and hope she ended up okay.