A guy in North Carolina sent a letter to a restaurant after he and his wife had lunch and accidentally stiffed their server. Days later, he realized he took the wrong receipt that had the tip on it, so the waitress didn't get the money.
The letter explained what happened, and he included a crisp $20 bill for her. The restaurant posted a photo on Facebook, and people are praising him for going the extra mile. (Here's a photo.)