Why did he say he did something bad?
He literally told them to try the food before criticizing his store and people; if that is doing "something bad," then I have no clue what his standards are.
I mean... this light and extremelypolite chastisement? That is nothing more than basic courtesy towards yourself, your profession, you business, and your family (through catenative assemblage, at least)!
For him to think he "did something bad" by merely asking a rude person to act correctly?!
That's not humility; that's stupidity.