I had a great experience on the train once. Sitting next to this elderly lady, she really wanted to talk so it seemed even though my Japanese is really poor. Anyway, we had a pleasant on and off chat and when I got off the train she gave me this handkerchief. I thought it was just a handkerchief, but later found out there was a crisp new 10,000 yen in it!!! And I couldn't even say thank you!