I remember a true story narrated by my housemate some 20 years ago when we were still undergraduate students in Canada.
She was on the bus on the way home after finishing class.
Along the way, the bus stopped and a very young boy ( at primary school age ) got on the bus. He paid the bus fare through the slot machine beside the driver, using a lot of coins.
After all the coins were in, then only he discovered to his horror that it was 10 cents short.
The bus driver let him sit on the bus anyway.
But the boy was obviously feeling upset. He told the driver that he will pay the remaining amount, sounding very guilty.
Before getting down from the bus the boy again told the driver that he will pay the balance. The driver simply nodded acknowledging his words.
Then the boy went down from the bus, but before the door was shut, he turned again to face the driver and said,
"I will pay, okay? Look.. Look at my face, remember my face.. remember me..I will pay, okay?"
That was really sweet of him. He was very concern that the bus driver would not recognize him or forgot his look and he just had to make sure that the driver had a good look at him.
The heartwarming and touching incidence was being witnessed by the entire bus passengers, including my housemate.
Prophet Muhammad (SAW) said, " Sin makes the heart restless".