At that point I stopped flipping through the cards, put them back in the box, and gave the guy a dollar. When I got home I went through the rest of the cards and found some more great/interesting/questionable photography.
Ever take a picture and then years later you regret it? How about minutes later?
Have you ever seen a picture on the front of a card and then wondered what happened right after that picture was taken.
Here are a few additional card backs that I found interesting.