This waiter's random act of kindness resulted in a wonderful piece of karma

A waiter in the US received a $500 tip on a 37 cents bill, all because of an act of kindness the day before.

Tipping isn't as big in the UK as it is in the US, but even most Americans would think $500 (£381) is a huge tip for 37 cents (28p) bill.

On Tuesday Kasey Simmons, a 32 year old waiter at an Applebee's restaurant in Dallas, served some customers the cheapest thing on the menu, flavoured water. He was shocked when they left a $500 tip, but the customers left a napkin to explain why.

On Monday Simmons had seen an older woman in a supermarket who looked forlorn and despondent. According to Simmons the woman did not explain why she was upset, but Simmons' conversation with her lifted her spirits. Then Simmons paid for her groceries. Speaking to ABC local news station WFAA he said:

It was only $17, but it's not about the money... It's about showing someone you care.

The note on the napkin explained that one of the customers was the older woman's daughter. The customer wrote that Monday had been the third anniversary of her mother's husband's death. Simmons elaborated on what else the message said to WFAA:

On one of the most depressing days of the year ... you made my mother's day wonderful...You insisted on paying. Told her she is a very beautiful woman. I have not seen this woman smile this much since dad died...My mother did not need you to help her, but you made her year!

Faith in humanity, duly restored.

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