Once, I was in line waiting on a woman with a newborn to finish up her check out process. She had misplaced her debit card and had no cash to pay for her groceries. It was awkward for all - until a man at the back of the line passed his card up and says, "here, I've got it. It's hard adjusting to a new baby." It was inspiring.
Today, more magic. A woman's account was lower than she thought and she had to sort through to figure out what to put back and what to keep because she didn't have enough money for it all. The man in front of me said, "how much do you need?" When the answer was, "about $15" he gave a $10 and the woman in front of him gave a $5. The woman in need was grateful and embarrassed. They told her not to worry, just pay it forward. She beamed and said "I know how I can! I have a friend just diagnosed with breast cancer and I'll help her with some expenses."
A great lesson that even mundane tasks like grocery shopping are opportunities to love your neighbor. Pretty neat!