This is a perfect example of good customer service and is exactly how business should properly be done. And yes, it’s definitely a WhitePeopleThing.
Good, friendly service is provided, and payment is rendered, a bit more than is necessary.
I used to do tech stuff for people in their homes. I really enjoyed the work. When people would ask what they owed I just said, honestly whatever you want to pay me as I’m not in it for the money. White people always paid well. Others, not so much, but I wasn’t expecting it so whatever.
And then when I worked in the auto service industry, I noticed the same trends. White people seem to intuitively understand how business is done. Others (especially middle eastern muds), absolutely not.