That's a wonderful story, wish there were more like that.
My husband was traveling in a city he didn't know. He stopped at a convenience store to buy a map book & a soda. At the counter he realized he left his wallet in the car. He left the stuff there and went to the car. By the time he got his wallet and started back to the store, the lady in line behind him came walking out of the store with his stuff, walked right up to him and said here, you forgot these. He tried to tell her that he hadn't paid for them yet but she waived him off and said everything was taken care of and she was late for work. He stood there in the cold for a while comprehending the whole situation. Went back in & the clerk verified the stuff was paid for by the lady. On the way out the door, someone said pay it forward.
He has, many times.
I tried to buy a soda for a guy once and he thought I was stealing it. Oh well.