My bank was changing their debit card services from one provider to another, and gave a set date when that turnover was supposed to take place. I'm notorious for not watching my mail for the new cards to arrive and not paying attention to their expiration dates. HOWEVER, the date of the turnover had not yet arrived.
Once a month, I have a chiropractic adjustment and a massage, and then go to a nearby restaurant and have my favorite meal. I only had enough cash on me to tip for the massage and my meal. After I ate and went to pay with my debit card, it was declined. I was confused, because I knew I had money in the bank. All was made clear when the restaurant manager informed me that all cards had been shut off the week before. I was mortified! I had no cash, and they didn't take checks...
A kind lady at a nearby table asked if there was a problem, and while I stood there stammering in my embarrassment, she handed me a ten dollar bill to pay for my meal. I was so grateful, I couldn't thank her enough. The next month at the same restaurant, I picked out a random family, a young couple with two small children, and paid for their meal and tip before I left.
This story is from Quora.