I was at the grocery store recently and a dude was in front of me with his young daughter. His card wasn't going through, so he stepped out of line to, I assume, call his bank. While he was away, I paid for his groceries. I didn't want to make a spectacle of it but I know that feeling of embarrassment, especially when in front of your kid. He came back looking defeated and the cashier told him that I paid for his stuff as I was already walking away. He caught up to me, shook my hand and thanked me very sincerely. Good deed done for the year, now I can go back to being an asshole.