This is an awesome story.
According to Reddit, Tampa Bay Buccaneers defensive end William Gholston ran out of gas on the freeway when he was a senior in high school.
He walked to the nearest gas station asking for help, with no money. The gas station clerk kindly helped out Gholston by filling his gas for free.
5 years later — Gholston now an NFL player — returned to that gas station and paid the man back, with interest.