I was in a bar one time and a family (it was that sort of bar) was eating in a booth near to where we were sitting.
A boy (maybe 14yo) got up from the table and dropped a bill........the guy in the table next to them picked it up nonchalantly. The boy didn't see it, and I thought they were all together or something.
Whne the bill came shortly afterwards, the boy announced that he was paying for this dinner, as a gift for his parent's anniversary.........only he couldn't find he $50 bill he intended to pay with.
I watched this go down, and the boy started crying........the SOB who picked up his money was staring the other direction pretending not to hear.
I HAD to do something.
To make a long story short, that **** gave the money back and has not set foot in that bar since.